To heal the most complex fractures, American researchers have created superior bone grafts from primitive stem cells. The latter would help to make very fertile scaffolds to help broken bones to regenerate.
- In the context of a complex fracture, a bone graft may be necessary. This usually comes from a bone belonging to the patient himself or to a corpse.
- But auto-grafting usually takes a long time while a graft derived from cadaver bone often lacks many biomolecules.
- To create a biologically active bone graft, researchers turned to the cellular ancestors of mesenchymal stem cells, pluripotent stem cells.
Most often, when we break a bone, the doctor plasters us and recommends that we arm ourselves with patience. However, some more complex fractures require treatment, and sometimes doctors turn to surgical procedures that involve transplanting bone tissue over the broken area. These grafts generally come from a bone belonging to the patient himself or to a corpse. However, these procedures have several drawbacks. Autografts require additional surgery to extract bone tissue, which increases recovery time and sometimes chronic pain. When grafts derive from cadaver bone, they tend to lack many biomolecules that promote bone repair.
“What we wanted to do was design a bone graft that would allow us to experimentally increase the speed, so to speak, and make it more biologically active.”explain the authors of a study whose results appeared in the June issue of the journal NatureCommunications. Here, researchers from the Texas A&M Health Science Center (USA) have succeeded in creating superior bone grafts from primitive stem cells. The latter would help to make very fertile scaffolds to help broken bones to regenerate.
Previous studies have shown that the stem cells, especially the mesenchymal ones, could be used to produce biologically active bone grafts. They transform into bone cells that produce the materials needed to make the extracellular scaffold or matrix that bones need to grow and survive. However, these stem cells are often taken from adult bone marrow and are therefore older, which affects their ability to divide and produce more extracellular matrices.
“A huge improvement on current bone repair technologies”
To circumvent this problem, researchers at Texas A&M University therefore had the idea of turning to the cellular ancestors of mesenchymal stem cells, pluripotent stem cells. The result: unlike adult mesenchymal cells, which don’t live long, primitive cells can continue to proliferate, producing unlimited mesenchymal stem cells, the scientists observed. This therefore allows a supply necessary for the manufacture of the extracellular matrix for bone grafts. What’s more, pluripotent cells can be made by genetically reprogramming donated adult cells, they enthuse.
To test the effectiveness of their scaffold material as a bone graft, the scientists extracted and purified the enriched extracellular matrix before implanting it into a bone defect site. Over the weeks, their pluripotent matrix derived from stem cells has become five to six times more effective than the best transplant stimulator approved by the Food and Drug Administration (FDA), they welcome.
“Bone repair tests using the gold standard of grafts, such as those given with the powerful bone growth stimulator called morphogen-2 protein, can take around eight weeks, but we were getting full recovery in four weeks., comments Dr. Carl Gregory, associate professor at the Texas A&M Health Science Center, also corresponding author of the study. ATthus, under these conditions, our material far exceeded the effectiveness of bone morphogen protein 2, indicating that it is a significant improvement on current bone repair technologies”he continues.
Large-scale manufacturing of bone grafts made easy
From a clinical perspective, grafts can be incorporated into many implants, such as 3D printed ones or metal screws. In addition, bone grafts will also be easier to produce and therefore advantageous from a manufacturing point of view.
“Our material is very promising because pluripotent stem cells can ideally generate many batches of extracellular matrix from a single donor, which will greatly simplify the large-scale manufacture of these bone grafts.”concludes Dr. Roland Kaunas, associate professor in the Department of Biomedical Engineering and corresponding author of the study.
In addition to fractures, in France, the bone graft can be used to treat bone cancer or osteoarthritis. It can also be performed as part of maxillofacial surgery, to permanently weld a joint or to replace an obsolete or dysfunctional joint prosthesis. The operation is performed under general anesthesia. As for the recovery period, it is more or less long depending on the operating site, the size of the graft and its ability to consolidate.
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