Some stem-cell news out of Stanford this morning: Researchers here have used a new method to ensure human embryonic stem cells survive - and are accepted by the immune system - in animal models. Why is this significant? In a release my colleague explains these cells' problem with immune-system rejection:
Just as it does with transplanted organs, the human body recognizes foreign cells and rejects them. Embryonic stem cells, or ES cells, and the tissues they become are by definition immunologically different from any potential recipient.
Currently most animal experiments involving transplanted stem cells rely on the long-term use of immunosuppressants to prevent rejection. Most ongoing human clinical trials also use the medications (with the exception of those in which the cells are transplanted into a body location, such as the eye, that is relatively protected from the immune system), which can cause hypertension, weight gain, organ damage and an increased susceptibility to infection. [Joseph Wu, MD, PhD,] and the study’s first author, graduate student Jeremy Pearl, wondered whether there were any other options.
The researchers used a short-term treatment with three immune-dampening drugs and found that this allowed the animals to accept the cells. They're now testing whether the drug treatment works in larger animals; the work, my colleague reports, may someday "allow humans to accept transplanted stem cells intended to treat disease or injury without requiring the ongoing use of powerful immunosuppressant medications."
The study appears in the March issue of Cell Stem Cell.