The treatment of diabetes is one of the most promising applications for regenerative medicine – replacing diseased with healthy tissue – because insulin-producing cells can readily be transplanted between people.
In the 1990s, James Shapiro and colleagues at the University of Alberta drew up the Edmonton Protocol for transplanting “islets”, groups of cells that make insulin to regulate glucose levels in the blood. This procedure has helped about 1,800 patients worldwide who have the most dangerous form of diabetes and cannot recognise potentially fatal changes in their blood sugar level. But its use has been severely limited by two factors, which biotechnology is beginning to address. One is the need for recipients to take immunosuppressant drugs indefinitely, to prevent rejection of the transplants. The other is that, at present, the only source of islets is the pancreases of deceased donors.
Shapiro is working with Sernova, a Canadian biotech company, to make better use of islets. The Cell Pouch, which recently started clinical trials, is a matchbox-sized device implanted under the skin; it provides an “organ-like” environment more conducive to cell survival and growth than the current transplant site, the liver.
A second innovation, being tested in animals, is a technology called Sertolin, designed to lessen the need for anti-rejection drugs. This is based on Sertoli cells, which make the testes an “immune-privileged” environment for developing sperm cells. If Sertoli cells have the same effect when added to a Cell Pouch, they will protect islets from immune attack locally, without the patient having to undergo systemic immunosuppression.
Researchers are also working on alternative sources of islets to overcome the shortage of donor pancreases. Shapiro is collaborating with ViaCyte, a San Diego company, on developing a diabetes treatment based on human embryonic stem cells. But these would still require isolation from the recipient’s immune system. Looking further ahead, “induced pluripotent stem cells” derived from the patient’s own skin cells may be a long-term option for making immune-compatible islets.
Other researchers are pinning their hopes on xenotransplants – islets grown in pigs, carefully screened for viruses and genetically engineered to be as compatible as possible with the human immune system. But these are likely to face a higher regulatory barrier than products based on stem cells.
Automated sensors and pumps, monitoring blood sugar and administering insulin as required, offer another approach. But Shapiro believes that in the long run biology will beat electronics: “I put my money on islets and stem cells.”
The hunt for a British baked bean
Baked beans are a dietary staple in the UK, with an average Briton eating 5kg per year. Yet none of these navy beans, which end up in tins smothered in tomato sauce, are grown on British farms; most come from Canada.
Now scientists at the University of Warwick are reviving a project of the 1980s, which came close to developing a navy bean for British growers but then lost momentum.
The basis for the new work at Warwick’s Crop Centre is a project by its predecessor, the National Vegetable Research Station, which came up with a new bean variety called Edmund 25 years ago. Farmers at the time did not feel it was quite right for the UK, where a shorter growing season and cooler summer than on the Canadian prairies might not allow reliable harvesting of dry beans.
Eric Holub, professor of plant genetics at Warwick, says the initiative is worth reviving, because new genomic techniques offer better ways to breed varieties for British conditions and because climate change has improved the prospects of growing navy beans profitably, especially in East Anglia and southeast England.
“A shortened growing season is most important: navy beans in the UK have to be harvested in September when it is still dry, to avoid autumnal damp weather, which causes them to discolour,” says Holub. “DNA sequencing will improve the ability of bean breeders to select new varieties by locating useful natural variation of desired genes.”
Andrew Tock, project leader, believes UK consumers, who buy hundreds of millions of tins of baked beans a year, would go for a homegrown product. “In addition to the potential market value, growers stand to make agronomic gains from incorporating a nitrogen-fixing legume crop into their rotations, which could promote soil renewal after repeated cereal and oilseed rape,” he adds.
Meeting of minds on a North Korean volcano
The Korean peninsula is a volcanic environment in a geological as well as a political sense – which is why North Korea is embarking on an unprecedented scientific collaboration with two countries that its leadership loves to hate, the US and UK.
The focus is Mount Paektu on North Korea’s border with China, where a catastrophic eruption 1,000 years ago covered 33,000 sq km with ash. Recent seismic activity has aroused fears that the 2,744m-high volcano may blow again. Last month British scientists installed sophisticated seismic instruments on Paektu at the invitation of North Korea, in an agreement brokered by the Royal Society in London and the American Association for the Advancement of Science (AAAS) in Washington DC.
These broadband seismometers are more advanced than anything available in North Korea. They will not only pick up any murmurs generated within the mountain but also detect seismic waves from earthquakes elsewhere in the world passing through Paektu.
“This should give us an image of the inside of the mountain, like a CAT scan,” says James Hammond, a seismologist at Imperial College London, just back from North Korea. His colleague, Clive Oppenheimer of Cambridge university, brought home 25kg of rock samples.
Scientists are keen to understand the unusual vulcanology of Paektu. Its eruption in the 10th century was one of the most powerful in recorded history, yet it is well away from the tectonic plate boundaries where volcanic activity is usually concentrated. The edge of the Pacific plate is hundreds of kilometres to the east.
This first substantive scientific agreement between North Korea and the west took two years to negotiate, because of the political sensitivities and the US and UK governments’ fears of a potential enemy getting hold of advanced electronics. “The biggest challenge of the project was obtaining all the export licences,” says Hammond.
The initial North Korean contact was with AAAS, which is funding some of the work. The Royal Society came on board because the selected scientists came from British universities. “We have a long history of science diplomacy,” says Martyn Poliakoff, foreign secretary of the Royal Society. “North Korea is one of the world’s most isolated countries, and providing a means of contact through high quality science is a terrific opportunity that can benefit everyone.”
Hammond calls the experience of working with the North Korean scientists “very positive”. “They are enthusiastic, and the sites they built for us are some of the best seismic stations ever deployed.”
The instruments record seismic activity on internal hard drives. The Koreans will send the data to the UK for analysis, before the British scientists return to Paektu next August. “It is not like a quick chemistry experiment,” says Poliakoff. “You have to wait for the mountain to speak to you.”
Meanwhile the British scientists are planning a longer-term collaboration with their North Korean colleagues. “They have been disconnected from the international geological community,” says Oppenheimer. “We want to bring some of them to the UK so that we can work alongside them here.”