At a glance
3D printing has been around since about the 1980’s. However there has been a huge explosion in advances to the technology making it incredibly cheap and popular to use. So much so, that 3D printers have moved from the realm of DIY tinkerers to fully fledged consumer products. In the meantime scientists have also capitalised on this technology to print everything from blood vessels, heart valves, ears and scaffolds to rebuild whole organs. Now a group of North American scientists have used it to produce a model that may benefit people with MS.
The researchers have published their results in the highly prestigious journal Nature. In this article they describe how they have used 3D printing to produce artificial human axons to study the effects of potential myelin repair therapies.
In MS, the immune system damages the insulating myelin layer on nerve fibres, disrupting the ability of the nerve cells to signal efficiently. There is a considerable research push to find compounds that will restore the myelin layer on nerve fibres. However, one huge hurdle scientists face in this hunt for the next generation of MS treatments is the expense and time required to test the numerous potential drugs for their effect on myelin repair.
Currently in the laboratory scientists use various systems to test the effects of medications on myelination. However these models are limited, some of them are created from materials, such as glass, that are much sturdier and more rigid than human nerves. Another approach is to use real nerve cells grown in a dish, but this is not practical nor feasible when there are a large number of different treatments to test.
The 3-D printed “axons” have similar physical and mechanical properties to the axons in the human brain and the scientists also have the ability to change the properties of the artificial axons to test and discover different aspects of myelination, and to mimic both healthy and damaged axons.
To prove that they work as a realistic model, the scientists grew cells that produce myelin, called oligodendrocytes in the presence of these artificial axons. The oligodendrocytes were able to adhere to the printed axons and produce myelin that wrapped around them, mimicking what happens in the human brain. They also found that if they made the fibres narrower and stiffer they were preferentially coated in myelin compared to the fibres which were fatter but more flexible.
This an exciting use of this ever improving technology. These 3D printed axons have the potentially to not only help scientists make fundamental discoveries about the myelination process, but it will help them to cheaply and rapidly screen large panels of potential drugs before moving on to human trials.