Researchers have shown that immune-defense cells influenced by embryonic stem cell-derived cells can help prevent the rejection of hearts transplanted into mice, all without the use of immunosuppressive drugs.
The University of Iowa and the Iowa City Veterans Affairs (VA) Medical Center finding has implications for possible improvements in organ and bone marrow transplantation for humans. The study results appeared Friday in the online journal PLoS ONE, published by the Public Library of Science, at http://dx.plos.org/10.1371/journal.pone.0003212.
People who need bone marrow or solid organ transplantation must take immunosuppressive drugs that can cause side effects nearly as severe as the disease they have. They also can experience graft-versus-host disease, which can cause death.
These problems are spurring researchers to develop methods to reduce transplantation rejection, said the study's principal investigator Nicholas Zavazava, M.D., Ph.D., professor of internal medicine and director of transplant research at the UI Roy J. and Lucille A. Carver College of Medicine.
"The idea behind the study is to 'prep' a recipient's immune system to make it receptive to the eventual organ or bone marrow donor's genetic make-up," said Zavazava, who also is a researcher and staff physician with the Iowa City VA Medical Center. "The approach involves taking embryonic stem cells with the same genetic background as the donor from which the organ or bone marrow ultimately will come and adapting them into another type of stem cell that can be injected into the recipient."
Specifically, the team treated mouse embryonic stem cells with a "cocktail" of growth factors, causing them to become blood stem cells. These cells express very low levels of so-called "transplantation antigens" and are therefore protected from immunological rejection.
|Contact: Becky Soglin|
University of Iowa