Stem cells are incredible because they can divide over and over for indefinite periods and give rise to various types of cells. As the National Institute of Health explains, “When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.” Asterias Biotherapeutics has been carrying out a study evaluating the spinal injections of neural cells produced by stem cells for patients with spinal cord injuries. This study, “SCiStar,” had an incredible impact on the motor function and life of Kris Bosen in April 2016. His surgeon, Dr. Charles Liu, shared some insights with Not Impossible on this development.
The SCiStar clinical trials inject “AST-OPC1” cells, which are neural cells known as oligodendrocyte progenitor cells produced from human embryonic stem cells, into the injured patient’s cervical spinal cord. Kris Bosen experienced a traumatic spinal injury in a car accident in March 2016 at age 20. He was paralyzed from the neck down when he signed up for this multicenter study at Keck Medical Center of USC. USC News explains that because the window for surgery after injury is tight and Bosen had to verbally agree to participate, he was weaned off a ventilator in an expedited fashion with the help of a respiratory care team.
Dr. Charles Liu is the Director of the USC Neurorestoration Center and was the lead surgeon working in partnership with Rancho Los Amigos National Rehabilitation Center and Keck Medicine of USC, to give Bosen a spinal cord injection of 10 million AST-OPC1 cells. Edward Wirth III, chief medical director of Asterias and lead SciStar investigator, said this is “a dose range that is the human equivalent of where we were when we saw efficacy in pre-clinical studies.”
Typical treatment for spinal cord injury includes surgery to stabilize the spine that has little effect on sensory or motor function levels. Bosen showed improvement two weeks after this procedure and three months later he experienced increased sensation and mobility in his arms and hands that allowed him to hug loved ones, use a cellphone, operate a motorized wheelchair, write his own name, and feed himself. Liu told USC News that he
“gained significant improvement in his motor function, up to two spinal cord levels. In Kris’ case, two spinal cord levels mean the difference between using your hands to brush your teeth, operate a computer or do other things you wouldn’t otherwise be able to do, so having this level of functional independence cannot be overstated.”
Liu told Not Impossible more about the spinal injection location:
“The injections were performed in the cervical spinal cord. The location was specifically chosen in this study because if two functional levels of recovery is evident, the improvement in function can be very dramatic in terms of what the patient can do for themselves, compared to say the thoracic region, where two functional levels would result merely in some improved sensation in the trunk.”
Liu also said that “Kris's preliminary recovery really exceeded our expectations in terms of functional restoration. Typically, patients such as Kris do not recover as much function after their injury. However, our enthusiasm is always tempered and best characterized by cautious optimism.”
The most exciting part of the study for Liu personally was “that we are actually moving forward to evaluate these ‘stem cells’ that have a chance to change the prognosis for patients' lives and allow them to be more independent.”
AST-OPC1 cells are made from stem cells and are converted into oligodendrocyte progenitor cells, which USC News explains are “cells found in the brain and spinal cord that support the healthy functioning of nerve cells.” These cells were found in lab studies to promote the survival, regrowth, and conduction of nerve impulse through axons (the part of a nerve cell along which impulses are conducted) at the injury site. The cells do this by producing neurotrophic factors (biomolecules that support neuron development) and stimulating vascularization (the development of vessels in tissue). They also induce remyelination (the generation of insulating myelin sheaths) around denuded (bare) axons.
USC News explains that this clinical trial is being carried out at six sites, that enrollees must be between 18 and 69, and that “their condition must be stable enough to receive an injection of AST-OPC1 between the 14th and 30th days following injury.” Liu shared his long-term hopes for this study with us:
“For the long term, my hope is that some paradigm involving regenerative medicine and stem cells will become generally available to spinal cord injury patients. For any early stage study involving transformative technologies, there are always three possibilities:
1) The technology is harmful to the patient (so far, no one who has received AST-OPC1 have been made worse);
2) The study has firmly established the technology as definitely useful (unlikely in any early-stage study);
3) The results are promising enough to encourage expanded and controlled evaluation of the technology (it appears that this is the case with the present trial).
Typically [the first] possibility is catastrophic and we are delighted that the present study does not fall in this category. All of the investigators in the present trial felt that possibility 2) would be highly unlikely. Since the present trial appears to be headed to possibility 3), all involved are quite delighted and cautiously optimistic about this approach.”