The stem cell toolbox has been a bit of a jumble, at least as far as joint-improvement projects are concerned. Scattered among bone marrow stromal cells (BMSCs) are stem cells that could be useful in treating arthritis—regenerating tissue, cartilage, and bone—but grabbing hold of them is difficult. BMSCs tend to look alike, even though some are capable of differentiation and some are not. Consequently, cell-based arthritis treatments have involved a degree of blind groping.
Arthritis treatments promise to become handier now that researchers at the University of York have demonstrated that different kinds of BMSCs can be identified and isolated from each other. Most important, these researchers have shown how to identify which BMSCs are stem cells capable of repairing cartilage of joint tissue, advancing the development of cell-based treatments against arthritis.
The York team presented its findings June 9 in Stem Cell Reports, in an article entitled, “Multiparameter Analysis of Human Bone Marrow Stromal Cells Identifies Distinct Immunomodulatory and Differentiation-Competent Subtypes.” This article described how the researchers used immortalized human BMSC clonal lines for multilevel analysis of functional markers for BMSC subsets.
“All clones expressed typical BMSC cell-surface antigens,” wrote the authors. “[However], clones with trilineage differentiation capacity exhibited enhanced vascular interaction gene sets, whereas non-differentiating clones were uniquely CD317 positive with significantly enriched immunomodulatory transcriptional networks and high IL-7 production.”
Essentially, the York team showed that distinct functional identities can be assigned to BMSC subpopulations, including those likely to have specific roles in bone homeostasis. In addition, the team isolated a rare subset of stem cells in bone marrow. These cells have no capability for tissue repair. Instead, they appear to participate in immune function.
“While stem cell therapy is an exciting new development for the treatment for osteoarthritis, up to now it has been something of a lottery because we did not know the precise properties of each of the cells,” said Paul Genever, Ph.D., the leader of the York team. “This project has helped us to establish which cells are good at regenerating tissue, cartilage, and bone, respectively. It will help in the search to develop more targeted therapies for arthritis patients.”