"The purpose of this experiment was to determine whether the procedure is safe and has enough promise to justify future research," said principal investigator Timothy Vollmer, M.D., associate professor of neurology at Yale School of Medicine.
The transplantation is part of a phase I clinical trial that is testing whether cells found in the body's peripheral nerves can safely repair the damaged cells in the brain and spinal cord that result in myelin disorders such as MS. In MS, the immune system attacks the brain's nerve fibers and strips away myelin, the protective sheath around nerve fibers in the spinal cord and brain, making it difficult for the nerves to transmit messages.
The myelin in the brain and spinal cord are made by cells called oligodendrocytes, which are attacked and destroyed in MS. The myelin in the peripheral nerves is made by Schwann cells. Animal studies show that Schwann cells can replace oligodendrocytes and remyelinate the demyelinated nerves in the brain and spinal cord.
Vollmer said he and his team want to determine whether the transplant of Schwann cells into the human brain is safe, and whether the Schwann cells actually survive in the adult human brain of a patient with MS. They also want to find out if the Schwann cells are able to wrap myelin around or restore the nerve fibers in the brain, restoring normal function.
The procedure took place on July 17 and 18. In the first 24 hours, the team isolated the Schwann cells from the sural nerve, which was removed from the patient's ankle. A neurosurgery team led by Dennis Spencer, M.D., then performed stereotactic surgery on the patient, using an MRI machine to very accurately guide a needle through the frontal lobe and inject the Schwann cells into a previously identified MS lesion.
Vollmer said the patient will now be studied using a number of techniques, including neuroimaging and functional assessments for six months. At the end of six months, the team will use the stereotactic procedure to take a small biopsy to determine whether the cells survived and whether they made any myelin.
The experiment holds promise, not only for the estimated 1.4 million people worldwide with MS, but also for patients affected by other demyelinating diseases, such as the leukodystrophies, a group of hereditary diseases that strike children in infancy.
Vollmer's team at Yale includes Jeffrey Kocsis, Dennis Spencer, M.D., Stephen Waxman, M.D., Adam Anderson, John Gore and others. The research is fully funded by The Myelin Project in Washington, D.C.