Written by Kranti Kaur

Children are always getting themselves into situations where they are susceptible to broken bones and other injuries. Thankfully, children heal faster than adults, so a broken bone in a child does not need months to heal itself. Rather, a few weeks are enough! But why do children have this special ability enabling faster healing than adults? The bones of children are thicker than those of adults. This may sound counterintuitive, but it is indeed true. Children have a significantly higher level of periosteum, which is vascular tissue that envelops their bones. This contributes to the increased thickness and strength of children’s bones. This layer of tissue is also responsible for the rate of healing, as the bones have higher levels of oxygen, which allows for a much more rapid mending process.

Additionally, because children are growing continuously, the resources that contribute to  growth are easily diverted to healing. Because adults are fully grown, it would take more effort to distribute that energy into healing, so it is a lengthier process.

One specific part of the body that children younger than two years old can heal is the skull.  Adults are not able to heal the skull at all, which magnifies the negative consequences of their head injuries. A recent study attempted to rectify this problem by adding stem cells to adult mice skulls that had been damaged. The method used to increase the amount of stem cells in the skull involved  stimulating cranial sutures, which are fibrous joints that serve to hold the various parts of the skull together. These sutures are significantly more prominent in babies, since their skulls are much more mobile as they grow, whereas adult sutures are fixed and immovable.

The study used a tool to stimulate these cranial sutures in the adult mouse skull. This resulted in a significant increase in stem cells, which are cells that are capable of replication and are able to differentiate into a wide variety of cell types; for example, a stem cell could turn into a specialized cell in the brain or the leg. Having these stem cells in the skull of the adult mice allowed for their skulls to heal without the need for bone implantations or other invasive treatments for skull damage.

The use of stem cells in the context of the study is mainly due to the fact that these stem cells are able to differentiate into specified skull cells, effectively regenerating the bone that was lost as a result of trauma. Even more outstanding was the fact that this method resulted in healing of defects that are not close to the suture itself. This opens up a new area of possible future research; how exactly do these stem cells move from the cranial suture to these areas with defects? How do these cells know to go to the defect and heal it?

There are limitations to this study, however. It was found that this method of treatment worked in two-month-old mice, but not in 10-month-old, or “middle aged” rodents. Two  months old roughly translates to young adulthood for mice, so it is interesting to see that although this result is something that is not naturally occurring, it does not work for the older mice. It was stated by Intini that the reason for the ineffectiveness of the treatment in older adult mice  populations is because they simply do not have as many stem cells as the skulls of younger mice. Because of the initial lack of stem cells, it makes sense that stimulating the cranial sutures would not produce as dramatic a result as it would in younger mice populations. Generally, this study was fascinating , as it opened up a new avenue of research into using the body’s established mechanisms to work for itself rather than using invasive procedures that can be significantly more risky for the patient. It is so exciting to think that in the future, a problem in the skull can be solved by the skull itself,