Stanford Medicine Newsletter Updates For the Local Community

 

First step toward testing stem cell therapy for spinal injuries

Gary Steinberg

   

In January, Stanford University School of Medicine became the third site in the country to participate in a landmark clinical trial to use human embryonic stem cells to treat spinal cord injuries. The trial, primarily designed to test the safety of these cells, will enroll up to 10 patients who have experienced recent paralysis below the waist due to spinal cord trauma.

The trial is based on work at Geron Corp. in Menlo Park and UC-Irvine in which researchers were able to coax human embryonic stem cells into becoming precursors to oligodendrocytes, neural support cells found in the brain and central nervous system. The oligodendrocytes help form the myelin sheath that insulates the nerves and helps the nerves signal to one another.

The principal investigator in the trial is Gary Steinberg, MD, PhD, a professor of neurosurgery and neurosciences at Stanford, who has been involved in stem cell research for neurologic repair for more than a decade. Steinberg and his colleagues will treat patients in the trial at the Santa Clara Valley Medical Center in San Jose, one of the largest referral centers for acute spinal cord injury and rehabilitation on the West Coast. The trial is run by Geron.

Stanford Medicine News recently spoke with Steinberg about the trial.

Q: What research suggests that these cells could be useful for treating spinal cord injuries?

Steinberg: Experimental studies demonstrate that when these cells are injected into the injury site of spinal cord-injured rodents, they migrate throughout the injury site and mature into functional oligodendrocytes. These cells rebuild the myelin around the axons, which help transmit electrical signals between nerve cells, and produce proteins that help support neurologic function. The result is improved movement in the treated animals.

Q: What steps are involved in preparing the cells and applying them to patients?

Steinberg: The human embryonic stem cells are specialized into the oligodendrocyte progenitor cells, which are evaluated for purity and frozen at Geron. The frozen cells must be thawed, tested for viability at the Stanford cell transplantation laboratory and delivered to the operating room at Santa Clara Valley Medical Center. Two million cells are then injected into the injured spinal cord in the patient, using a specially designed syringe positioning device that precisely controls the needle placement and penetration into the injury site.

Q; How will you monitor patients and determine whether the cells have worked effectively?

Steinberg: The primary goal of the study is safety. Patients will be given standardized physical examinations and neurological testing before and after the injection of the cells and at specified times for a year to monitor safety. The secondary goal—whether the cells are effective—will use similar testing to look for signs of return of sensory function or motor function for a year after injection of the cells. The patients will be monitored for 15 years after cell administration.

Q: What are your greatest hopes for this trial?

Steinberg: The greatest hope is that the cells are found to be safe after injection into the injured spinal cord of patients paralyzed below the waist from spinal cord trauma. We don’t expect to cure paralysis. It’s possible that if this study demonstrates the safety of the cell delivery, larger clinical studies will improve sensation, motor function or bladder/bowel control in future patients.

Q: Stem cells have been touted as having so much promise. How do you temper the expectations with the day-to-day realities of science, which are very incremental?

Steinberg: Translating stem cell therapy from the laboratory into the clinic is tremendously important. Since people are significantly different from rats or mice, we learn a great deal from clinical trials that we can never learn by studying animals.

While stem cell therapies hold much promise for treating many diseases, there is also considerable hype and unrealistic expectations. We should realize that advances in medical therapeutics usually occur in small steps, rather than quantum leaps.

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