A study has recently been published online in a journal called ‘Nature’ which suggests that it will be possible to grow transplantable human tissue using another species as a host. The researchers behind the study, Hiromitsu Nakauchi and his colleagues proved that mouse pancreatic islets could be grown inside rats and then transplanted back into diabetic mice. Immature stem cells capable of giving rise to several different cell types (known as pluripotent cells) were injected into embryonic rats that were incapable of growing their own pancreases.
When the rats were born and became adults, their pancreases, comprising mostly of mouse cells, were transplanted back into diabetic mice. The pancreases were able to sustain blood glucose levels in diabetic mice for more than a year after transplantation with just five days of immunosuppression. The study noted that the pancreatic islet transplants for diabetes provided a ‘clinically relevant model’ to address the question of stem cell transplant survivability.
The research has shown that there may be a future solution to the problem of organ donor efficiency. It is linked to developments that have taken place in stem cell technology over the last few years and the study has demonstrated that it is possible to grow and successfully transplant an organ from the body of one species into the body of another. The researchers stated that organ transplantation “remains the only cure for a growing number of patients suffering from a broad range of debilitating and fatal diseases,” and drew attention to the fact that there are currently over 76,000 patients in the U.S. who are waiting for a transplant operation.
Applying the technique to human patients is still a long way off as there are many technical hurdles to overcome and the technology is still in its nascent stages. The next phase will involve trying to generate human organs in animals that are closer to humans in size and the evolutionary ladder such as sheep, pigs, and primates. Human parts have already been grown on other species as a host including a human ear on the back of a rat. But transplanting human tissue from an animal host into a human being has not yet been done. There are also ethical and legal issues revolving around any stem cell-related applications including which kinds of stem cells can be approved for human applications.
Nakauchi and team have been pioneers in the field by proving that pluripotent stem cells can reproduce replacement cells and tissues in any number required. They have also established that the new cells and tissues can survive a transplant and normalize and function well after it has taken place. Further developments and improvements will bring their goal of applying the method for human application closer to fruition.