Researchers at University of California (UC) Davis Health System will be part of a nationwide study to examine whether one single injection of adult stem cells directly into diseased lumbar discs can repair and regenerate them, relieve chronic low-back pain, and possibly avert spine surgery.
The study will test the safety and efficacy of the use of mesenchymal precursor cells (MPCs) -- adult stem cells derived from bone marrow that have the potential to replace bone, cartilage, and muscle -- in treating diseased lumbar discs and relieving pain.
The study's principal investigator is Kee Kim (pictured), associate professor and chief of spinal neurosurgery at UC Davis Health System.
"Many scientists and clinicians have injected all different kinds of material into the degenerated disc, hoping that something good will happen. Thus far, we have not been very successful, but we hope that a stem cell-based therapy will be the answer that we have been seeking for decades," Kim said.
An estimated 30 million people in the United States suffer from back pain. Degenerative disc disease is the most common cause of low-back pain, which develops with the gradual loss of a material called proteoglycan, which cushions the bones of the spine and enables normal motion.
Most patients with low-back pain respond to physical therapy and medications, but in advanced cases, artificial disc replacement or spinal fusion -- removal of the degenerated discs and the fusion of the bones of the spine -- is necessary. However, these surgeries often are not entirely effective, and additional surgery may be required to address sometimes serious complications.
The study will be the first of its kind in the United States, Kim said. Researchers will enroll approximately 100 study participants. Ten will be enrolled at UC Davis, and the rest at 11 other medical centers throughout the country.
For the study, Kim and his colleagues will enroll study participants who have suffered from moderate low-back pain for a minimum of 6 months and whose condition has not responded to other, conventional treatments.
Once enrolled, the patients then will be divided into four groups:
- One group will receive a high dose of MPCs, plus hyaluronic acid, a substance that facilitates the localization and retention of the stem cells
- A second group will receive a lower dose of MPCs, plus the hyaluronic acid
- A third group will receive the hyaluronic acid alone
- A fourth group will receive only the saline solution
Kim said that, by using saline in one of the two control groups, researchers will be able to determine whether hyaluronic acid is itself a factor in aiding disc regeneration, or whether it causes any adverse reactions.
"As an investigator, the design of this study is one of its most attractive features. This type of randomized study where the patients are blinded to the treatment is as good as it's going to get to eliminate any possible bias," Kim said.
At UC Davis, Kim will collaborate with Scott Fishman, professor and chief of pain medicine and co-principal investigator, to monitor patients' progress.
"Stem cell therapy for back pain offers the possibility of significant pain relief as well as, for the first time, renewal of tissues, which may prevent further degeneration and pain," Fishman said. "These are exciting times as we explore novel approaches that promise much more substantial and long-lasting benefits than ever before."
"Dr. Kim will initiate a very exciting adult stem cell study that reflects the importance of regenerative medicine in today's society," said Jan Nolta, director of the UC Davis Institute for Regenerative Cures. "Studies like the one that Dr. Kim is starting have the goal of fully repairing the damaged tissue. The hope is that stem cell-mediated repair will reduce or eliminate entirely the need for continued pain relief medication."
Mesenchymal precursor cells have been shown to reverse degeneration by producing proteoglycan. In pre-clinical studies on sheep with discs that were damaged or degenerated, a single injection of the stem cells was found to make the discs indistinguishable from healthy ones.
In contrast, disease progression was noted on imaging in two control groups of sheep that were either not injected, or injected with hyaluronic acid.
The agents will be injected directly into the center of the target discs. Patients will be monitored using imaging to identify any positive changes in their disease condition or disease progression. Use of pain medications, self-reports of pain, subsequent surgical interventions and assessments of disability, quality of life, productivity, and activity will be evaluated.
Kim also is involved with a parallel study on patients with more advanced disc degeneration, in which participants who had undergone removal of a cervical disc were injected with the stem cells to promote fusion of the vertebrae.
If MPCs are found to be safe and effective in this patient subgroup, they may one day be used instead of surgeries to address loss of disc height and other problems.
Kim said that it is premature to speculate about the role of MPCs in the treatment of back pain. Patient enrollment for the moderate low back pain study is currently underway and the trial is scheduled to last for 3 years.
"If safety and efficacy are shown in the study, this would be revolutionary. It would imply that we can possibly turn back the clock on aging by not only stopping the progression of degenerative changes in the disc, but also reversing the degenerative process," he said.
Illustration: University of California, Davis Health System.
University of California, Davis Health System News Release (11/29/11)
ClinicalTrials.gov: Safety and Preliminary Efficacy Study of Mesenchymal Precursor Cells (MPCs) in Subjects With Chronic Discogenic Lumbar Back Pain