Developing tissues from stem cells might get a lot easier due to a new technique that quickly identifies a certain type of stem cell from bone marrow based on a trio of biomarkers. The research was led by Krystyn Van Vliet of MIT and lead author W.C. Lee of the Singapore-MIT Alliance in Research and Technology (SMART). The results have been accepted for publication in the Proceedings of the National Academy of Sciences.
Mesenchymal stem cells (MSCs) can differentiate into many tissues like bone, fat, cartilage, and muscle. For this reason, scientists are very interested in using these progenitor cells in order to create replacement tissues for those who have been injured or who have disorders that prevent normal tissue growth. Within bone marrow, true MSCs are very hard to distinguish from cells that have already had their fate determined for a particular cell type due to molecular markers on the cell surface. This ambiguity of cell type is preventing work with bone marrow-derived MSCs from being as successful as they could be.
“Some of the cells that you’re putting in and calling stem cells are producing a beneficial therapeutic outcome, but many of the cells that you’re putting in are not,” Van Vliet said in a press release. “Our approach provides a way to purify or highly enrich for the stem cells in that population. You can now find the needles in the haystack and use them for human therapy.”
This new method has identified biomarkers that indicate a cell is truly multipotent and has not already begun to differentiate. While stem cells are typically smaller than cells that have begun to differentiate, not all of the smaller cells are stem cells. The researchers needed to identify other factors -- such as cell rigidity and the level of fluctuation within the cell's nuclear membrane -- that could be used to separate the pluripotent stems from those that are not. This method of identification will allow scientists to obtain a purer sample of MSCs for research and clinical use than have previously been used.
“Instead of putting in 30 percent of the cells that you want, and 70 percent filler, you’re putting in 100 percent of the cells that you want,” Van Vliet continued. “That should lead to more reliable patient outcomes, because you’re not going to have this variability from batch to batch, or patient to patient, in how many of each cell population are present.”
The method was tested by injecting the stem cells into mice who had sustained muscle and bone injuries. Mice who received MSCs with the new method were able to quickly regenerate both bone and muscle, while other mice who received bone-specific progenitor cells only saw rapid bone growth.
The team hopes to take this method into clinical trials for bone regeneration and are working on a new method that will speed up the identification process, allowing MSCs to be identified more rapidly.