Researchers Suggest Use of Bone Marrow Cells to Damper Immune Rejection of Transplanted Organs or ESCs

Using cells from mice, scientists from Iowa and Iran believe that they came up with a way to make embryonic stem cell transplants less likely to be rejected by a recipient's immune system. The strategy involves fusing bone marrow cells to embryonic stem cells. Once fused, the hybrid cells have DNA from both the donor and recipient, raising hopes that immune rejection of embryonic stem cell therapies can be avoided without drugs, the researchers explain.

“Our study shows that transplanted bone marrow cells fuse not only with bone marrow cells of the recipient but with nonhematopoietic cells, suggesting that if we can understand the process of cell fusion better, we may be able to target certain organ injuries with the patient's own bone marrow cells and repair the tissues,” points out Nicholas Zavazava, M.D., Ph.D., a University of Iowa researcher involved in the work.

Details appear in the February issue of The FASEB Journal in a paper titled “Cell fusion of bone marrow cells and somatic cell reprogramming by embryonic stem cells.”

Dr. Zavazava and colleagues used two different mouse strains, one as the donor and the other as the recipient. When bone marrow cells were engrafted into the recipient, they tested for the presence of both donor and recipient cells and found three different types of cells: donor cells, recipient cells, and fused cells that had DNA from the donor and recipient.

They then discovered that these cells could fuse with many different types of cells in addition to embryonic stem cells, including those from the liver, kidney, heart, and gut. In contrast, after cell fusion with embryonic stem cells, bone marrow cells were reprogrammed into new tetraploid pluripotent stem cells that successfully differentiated into beating cardiomyocytes.

The data thus suggests that cell fusion is ubiquitous after cellular transplants and that the subsequent sharing of genetic material between the fusion partners affects cellular survival and function. Fusion between tumor cells and bone marrow cells could have consequences for tumor malignancy.

Although more work is necessary to determine the exact clinical outcomes, the discovery raises the possibility that bone marrow cells could be fused to transplant organs to reduce the likelihood of rejection, according to the investigators. They could also be fused to failing organs to support regeneration, they add.