Insulin injections seem to be the only weapon diabetics have against coma, and even death. But not only are these injections painful, the blood-sugar balance may still fluctuate enough to damage blood vessels, leading to blindness, kidney failure, and amputations. Further, techniques for transplanting healthy insulin-producing cells from another human are handicapped by a lack of enough pancreas, where these cells reside, to go by.

But now a Swedish group of researchers led by Carl Gustav Groth of the Karolinska Institute in Stockholm and Claes Hellerstrem of the University of Uppsala have found that the human body can sometimes accept pancreatic cells transplanted from pigs. The investigators are now aiming to increase the yield of insulin from these cells, which do not produce enough to have an impact on the patient's diabetes (The Lancet, Vol 344, No 8934).

The Swedish team tried out 2 approaches to transplant the pig cells into diabetics. In 8 patients, pancreatic cells from pig foetuses were injected directly into the vein that feeds the liver; in 2 others, the injections were made under the capsule that surrounds the kidney. All the patients had undergone kidney transplants, and all were receiving drugs that helped to prevent immune rejection.

While pig cells in 6 patients were rejected within days, the porcine cells survived in the remaining 4 patients for upto 14 months, secreting a protein that suggested they were manufacturing insulin. But why some patients accepted the cells while others did not is still a mystery.