In Mice, Regulatory T Cells Improve Survival of Grafted Neurons in Parkinson's Disease Cell Therapy

Adding regulatory T cells to a cell replacement treatment for Parkinson's disease can help the survival the grafted midbrain dopamine neurons (mDANs), according to a new study in Nature. Previously, grafted mDANs — the loss of mDANs leads to the motor dysfunction seen in Parkinson's — exhibited poor survival, but researchers from Harvard Medical School have now found in mice that the surgical procedure itself triggers inflammation and an immune response in the brain. But co-transplantation of regulatory T cells, which are involved in immune homeostasis, regulating inflammation, and more, dampened the effect of needle trauma, including cell deaths, and boosted the survival of the grafted cells, the researchers report. "Initially, just one or two weeks after transplantation, the majority of the dopamine neurons died, rendering the cell therapy unsuccessful," corresponding author Kwang-Soo Kim from McLean Hospital says in a statement. "But when we added regulatory T cells to the transplant, survival of the grafted dopamine neurons increased. Also, behavior recovery was faster and more robust." Kim adds that the next steps are to examine the safety of such transplants, better understand how regulatory T cells protect the neurons, and to enhance their effect.