Stem cells are a potential treatment for disc degeneration, spine surgeon says

Though it may not yet be efficacious, current progress could pave the way for therapy.

Stem cell treatment could one day be a feasible and efficacious way to handle disc degeneration, according to a recently presented study.

The findings were presented by Todd J. Albert, MD, at the 24th Annual Meeting of North American Spine Society, in San Francisco.

“I think everyone in the audience knows the enormous problem of disc degeneration both in direct and indirect costs, as well as the millions laid waste to this disease,” Albert, a member of the Orthopedics Today Editorial Board, said. “Our expectations have to be in line with what we can achieve.”

Reliable biomarkers

The most important factors in stem cell treatment, he added, are reliable biomarkers of who will degenerate, stem cell sources, the ability to create nucleus-like cells, and the models necessary to advance to human treatment.

Todd J. Albert

Albert pointed out that there is a defined stage of disc degeneration, and to appropriately treat degeneration with regeneration it is necessary to identify patients before they get to the point where the disc can no longer be saved.

T2 mapping, Albert said, is an effective technique to study the disc, as it is predictive of the stages of degeneration in knee cartilage. His team took 18 rabbits and created a stab model with degeneration, then used standard MRI coils to define and measure echoes. These were then converted into a mathematical equation and used to make “a very clear vision of the disc” as they went through degeneration.

“You can very clearly measure this,” Albert said. “We found that quantitative T2 mapping is possible. We are now turning this into a human study, to look at patients with various stages of back pain to see if we can use this as a biomarker and a predictor for those who are going to degenerate.”

Treatment with reversine

Albert also talked about driving stem cells down a nucleus line by taking committed cells from a large source – such as the annulus – and turning them back into stem cells in the effort to repopulate the disc.

Reversine, a purine analog, reportedly takes cells backwards along their committed pathway and leads them to act like stem cells. Albert said his group wanted to see if this conversion could be used to create multipotent stem cells and commit stem cell lines to the skeletal lineage.

The team placed annulus cells in reversine for 4 days and then checked on their osteogenic, adipogenis and chrondrogenic differentiations. They found that the process was not toxic to the cells. In addition, Albert noted, it aided proliferation and induction of hypertrophy of the annulus cells and offered “fantastic” promotion of chondrogenics.

“Reversine treatment alters the expression of multiple genes linked to cell growth, cell cycle and differentiation,” he said. “Pretreatment enhanced the commitment of annulus fibrosis cells to mesenchymal lineages, and the chondrogenic lineage is favored over adipogenic and osteogenic phenotypes.”

“It is happening”

Albert concluded by asserting that stem cell treatment of disc degeneration is less a question of “if” and more a question of “when.”

“Disc regeneration is not only feasible, it is happening,” he said. “It may not be happening effectively yet, but the fact that it is happening means it is in the future ultimately going to be happening effectively. The bottom line is it is possible and may well be successful going into the future with careful scientific study.” — by Robert Press

Reference:

• Albert TJ. Stem cell treatment of disc degeneration: Preclinical studies. Presented at the 24th Annual Meeting of the North American Spine Society. Nov. 10-14, 2009. San Francisco.

• Todd J. Albert, MD, can be reached at The Rothman Institute at Thomas Jefferson University Hospital, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107; e-mail: tjsurg@aol.com.

Cell therapy may not be as safe as we think. There is a potential for mitogenic and neoplastic transformation, and in perusing the literature, there are some sarcoma cases — particularly when you have these mesenchymal stem cells going through many passages.

Cell therapy obviously has some potential, but the safety and efficacy concerns are greater than those of protein injection. Not to mention the FDA and regulatory process, which is going to be so huge that in my lifetime I don’t think it will be widely used or efficacious.

— Howard S. An, MD
Director, Division of Spine Surgery and Spine Fellowship Program
Rush University Medical Center