According to scientists, transplants of cells from baby pigs could be used to cure diabetes patients within three years after promising experiments in monkeys.
Two new studies have noted that islet cells from the pancreas of newborn piglet, that produce insuline, can reverse diabetes type 1 in primates. The findings, coming from Canadian and US scientists, make human clinical trials possible.
If the trials are successful, millions of patients suffering from type 1 and type 2 diabetes will have an opportunity to use therapy with piglet cells.
Transplants of islet cells that produce insulin have long been taken into consideration as a very promising treatment. The first experiments with human cells were organized in 1977.
Although the procedure has had promising results, prospects have been limited by a serious deficiency of human tissue for transplantation, which usually requires islets from two donors after death. In Britain, only a number of 800 donor pancreases is available for transplant each year. Scientists got interested with pigs as a possible source of islet cells because these animals have insulin that is similar to human insulin.
However, taking tissue from animals cause ethical and safety concerns because they increase the risk of introducing viruses as well as other pathogens that might be harmful.
Pigs carry so called porcine endogenous retroviruses (PERVs) which are a part of the animals’ genetic code. The viruses are harmless for the pigs but scientists are afraid that they could provoke diseases in humans.
In Britain, there is currently a moratorium on xenotransplantation, although human experiments using islet cells from pigs have been organized in Mexico.
The new research, one conducted by the University of Minnesota and the other conducted by the University of Alberta, checked the potential of islet cells from newborn baby pigs transplanted into diabetic rhesus macaque monkeys. Both reports are published in the journal Nature Medicine.
The transplants of Alberta study worked so successfully that the four monkeys have been able to quit insulin injections, one for nearly one year. The Minnesota scientists had similar results.
The transplants show that all the procedure is probably safe. Professor of Surgery at the University of Alberta, Ray Rajotte, stated: “The next step is to prove that these neonatal porcine islet cells could become a source for human transplantation.”
If the technique is to work in people, it requires them to take immunosuppressant medicine in order to minimise the risk of rejection of the pig cells. And this brings side effects, making transplants a less attractive choice for patients whose disease is adequately controlled with insulin injections.
In the longer perspective, human embryonic or adult stem cells will be probably
used to develop islet cells for transplant, which could be cloned as a ideal genetic fit
for people or matched from stem cell banks. Islet project co-ordinator at Diabetes UK,
Jo Brodie, stated: "A major limiting factor in the use of either whole pancreas or islet cell transplantation is the lack of available donor organs.
"This research offers the potential for a new source of islet cells."
LINK TO OBESITY
- Diabetes has two forms. In type 1, or early-onset diabetes the islet cells of the pancreas don’t produce insulin, a hormone that is necessary to metabolising sugar
- The type 2 or adult-onset diabetes is when the body is resistant to insulin, and it is often related to obesity
- About two million people in the UK suffer from diagnosed diabetes, about 75 per cent of them with the diabetes type 2.
- It is predicted that by 2010 the figure will increase to three million, mainly as a result of obesity causing more type 2 diabetes
- Islet cell transplants are claimed to be a promising therapy for the disease
