Mesenchymal Stem Cells Show Promise in Preclinical Studies of MS

The therapeutic administration of mesenchymal stem cells can improve functional abilities and promote the restoration of lost myelin in rodent models of multiple sclerosis (MS), according to a new analysis of published studies.

The findings highlight the potential of these stem cells, but also point to a need for more research on how best to use them as a treatment.

Results were published in Frontiers in Immunology, in the study “The Efficacy of Mesenchymal Stem Cell Therapies in Rodent Models of Multiple Sclerosis: An Updated Systematic Review and Meta-Analysis.”

Mesenchymal stem cells, or MSCs, normally reside in several types of tissue, including bone marrow and fat. Like other stem cells, MSCs are able to grow and differentiate into other kinds of cells. They are also able to affect the behavior of nearby cells by secreting chemical messengers.

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In recent years, MSCs have attracted interest in MS, because through their varied biological activities, these cells tend to have anti-inflammatory and wound-healing effects.

Some early research has suggested that MSCs could be beneficial in MS, improving function and restoring myelin — the fatty wrapping around nerve cells that is lost in MS. However, other studies have found contradictory results.

Now, researchers in China have conducted a meta-analysis of studies that tested MSCs in rodent models of MS. A meta-analysis is a technique where scientists pool data from multiple published studies, and analyze the data collectively. Since meta-analyses use more data than individual studies, they have more statistical power to draw reliable conclusions.

The team analyzed 88 studies that tested MSCs in rat or mouse models of MS. The oldest study was published in 2005, and the most recent was published this year.

The researchers noted that the studies used a variety of different techniques for MS treatment. For example, some used rodent MSCs, while other used MSCs from humans, and some MSCs were isolated from the bone marrow, while others came from different tissues. The timing and method of MSC administration also varied from study to study, and several different models of MS were used.

The team also noted that some of the studies were not of very high quality, which is inherently a limitation of this kind of analysis. “Because of a lack of rigor in study design or methodology in parts of a particular study, our conclusions are tempered by the low quality of the studies included in our analysis,” the researchers wrote.

Since there were study-to-study differences in how the efficacy of treatment was assessed, the researchers used data from each study to calculate a “clinical score” reflecting whether and how MSC treatment affected functional ability, and a “remyelination score” to calculate the effect of treatment on lost myelin.

Results showed that MSC treatment was associated with significant improvements in both scores. Significant improvements in the number of oligodendrocytes — the brain cells responsible for making myelin — also were noted.

“Overall, our updated meta-analysis comprising 88 studies suggested that rodents with MS benefited from MSC therapy as manifested by significant amelioration of functional and histopathological [tissue-related] outcomes,” the researchers wrote.

The team noted some trends in how techniques affected outcomes. For example, in the rodent models, using MSCs from rodents tended to yield more benefits than MSCs from humans. However, in many cases, there weren’t enough studies to do reliable comparisons between different methods.

“As many open issues are still unsolved, larger and longer-term trials are warranted to determine the more favorable parameter of MSC transplantation and to further evaluate the potential of cellular therapy in MS,” the scientists concluded.