|Motor neuron progenitors (green) derived from human embryonic stem cells. Death of motor neurons is a hallmark of ALS. Image: Sharyn Rossi, Hans Keirstead Lab at the University of California, Irvine|
A presentation at the International Society for Stem Cell Research today suggests that the biggest challenge facing the team has been how to deliver enough cells to the spinal cords of these patients, have them stay where they are needed, and not cause more injury to the patient.
The challenge: inject the cells slowly so they don’t leak back up the needle, do this while the patient’s spine is moving with every breath they take, get the cells into the “grey matter” of the spine where they will do good and not into the “white matter” that could do harm. Their solution: build a little mini-construction site on the patients’ backs.
Images shown by Emory University’s Nicholas Boulis gave me flashbacks of putting myself through college by spending my summers building interstate highways. All those rivers of concrete aren’t just poured on the ground. The area is surveyed to determine the right elevation(my job), carefully graded, and then paving forms are laid down to create a kind of rail road track for the paving equipment to precisely place ten inches of concrete.
Boulis developed a system to fix mini stationary rails on the backs of the patients that would move up and down with each breath of the patient. A platform holding the needle can then be moved along the track to deliver injections to a number of sites at precisely the right depth into the grey matter, and slowly enough the cells don’t leak out. This takes about two minutes for each injection.
The Emory team’s current project uses fetal neural stem cells developed by the Maryland biotech company Neuralstem. But he is working with teams around the country to also use his system, so that as teams report data using different types of cells or cells genetically programmed to provide a nerve growth factor, the results will be easier to compare. Researchers will know the cells were delivered in a ways that were equally likely to get to the right spot, stay there, and not cause damage.
Each team that plans to use the equipment will be required to come to Emory and practice on pigs, watch Boulis perform a procedure on a human patient, and then have Boulis come to their center so he can observe them do their first procedure. He has already started working with CIRM grantee Clive Svendsen at Cedars Sinai on a clinical protocol he hopes to begin in the next year or so. You can read about that project here.