Scientists in Japan have reported the production of mice that have rat's organs. They suggest one day this technique could be used to grow spare human organs in another species such as pigs, easing organ shortages and reducing long waiting times for transplants.
The researchers genetically engineered mice so that they developed without a pancreas, an organ that produces hormones such as insulin, which is deregulated in individuals with diabetes. They then took iPS cells from rats and injected them in to blastocysts from the genetically modified mice. They found that the resulting mice developed with pancreases formed almost entirely from the rat iPS cells. The pancreases appeared to be functional and the mice showed no signs of diabetes.
Professor Hiromitsu Nakauchi, director of the centre for stem cell biology and regenerative medicine at the University of Tokyo presented the study at the annual conference of the European Society of Human Genetics, held in the Netherlands. He said: 'The technique, called blastocyst complementation, provides us with a novel approach for organ supply. We have successfully tried it between mice and rats'.
The research team also reported the production of pigs that could generate human blood by injecting human blood stem cells in to pig embryos. Professor Nakauchi said: 'Our ultimate goal is to generate human organs from iPS cells'.
iPS cells are adult cells that have been engineered to behave like embryonic stem cells and can form any cell type in the body. In theory, therefore, in the case of a non-urgent transplant such as a kidney transplant, the technique could be used to grow an organ from iPS cells formed using the patient's own cells. This may reduce the risk of the transplant being detected as 'foreign' and rejected by the body's immune system.
Professor Chris Mason, chair of regenerative medicine at University College London, told the Telegraph that the technique 'could be a potential way forward' but that it was 'a very long shot requiring sustained resources and major finance for its testing and development'. He added: 'There is a long way to go before it could result in useable transplants, but it is an exciting vision'.