First artificial trachea implants breathe life into tissue engineering
The promise and potential of stem cell therapy has garnered much attention from the media over the years. Countless stories have been reported of groundbreaking stem cell research and that these discoveries are likely to change the way we conduct health care. However, sometimes stem cells alone aren’t enough. Don’t get me wrong: I am a big proponent of stem cell therapies, but I also like to take a step back and look at other technologies that may have just as much clinical impact. I am especially intrigued by seemingly simple innovations that incorporate biomaterials with the potential to revolutionize health care.
One such technology recently caught my attention. Kaiba Gionfriddo was born with an anatomical abnormality that caused flattening and weakening of his trachea, or wind-pipe. This made it difficult for him to breathe on his own. Doctors tried everything to help the infant, but their available arsenal of weapons was insufficient.
That’s when they turned to Glenn Green, a pediatric otolaryngologist, and Scott Hollister, a mechanical engineer, both from the University of Michigan, to see if they could help. These two researchers have developed a custom-made 3D printed tracheal splint designed to hold the trachea in place and keep the airway open until it can grow stronger and heal itself, while at the same time designing the device to slowly degrade away.
Their material of choice was a biodegradable polycaprolactone – a type of polyester material that has previously been used in other Food and Drug Administration (FDA) approved implant devices. Based on CT scan images of Kaiba’s trachea, the splint was designed to fit perfectly. The dimensions were fed into a computer and the device was fabricated using 3D printing technology. (I guess it’s not just for toy hobbyists or gun-makers anymore.) But let’s leave the topic of 3D printing for another post and 4D printing has been covered by my colleague here.
The entire manufacturing process of this tracheal splint is described in detail in a video available online. This new device obtained emergency clearance from the FDA through an accelerated approval process making Dr. Green and Dr. Hollister’s vision a reality when their 3D printed splint was successfully implanted and saved little Kaiba’s life.
Another promising novel biomaterial based technology to treat tracheal dysfunction also captured the media’s attention recently. Spearheaded by Paolo Macchiarini from the Karolinska Institute, the implantation of tissue-engineered tracheas in patients is currently underway and has seen tremendous success.
These artificially created living tracheas begin with a porous material engineered into a Y-shaped scaffold, which was developed by Alex Seifalian of the University College London Medical School. The material consists of a composite of polyhedral oligomeric silsesquioxane and poly(carbonate-urea) urethane, otherwise known as POSS and PCU for those of you cringing at the sight of chemical nomenclature.
POSS provides suitable surface properties to allow cellular adhesion, while the PCU imparts biostability to the scaffold, and the composite as a whole has been shown to be non-toxic and biocompatible with no incidence of inflammation. The scaffold is then seeded with the patient’s own stem cells and placed in a specially designed bioreactor system until it is ready to be implanted into the patient.
A recent Signals Blog post described the youngest patient to ever receive Dr. Macchiarini’s treatment and although the 2-year-old girl recently passed away from complications unrelated to the new trachea, she profited and others still do from this groundbreaking therapy.
Both of these technologies have allowed patients to breathe freely once again and highlight the importance of biomaterials. Interestingly, Dr. Green’s and Dr. Hollister’s tracheal splint consisted only of a biomaterial component and yet this simple piece of plastic (albeit carefully designed) was sufficient to save a life. To the keen observer, it reiterates the point that sometimes the simplest idea is the best.
This, however, does not take anything away from Dr. Seifalian’s and Dr. Macchiarini’s work; together they have developed an elegant technology to give life back to patients. It is collaborations like this, between biomaterial scientists and clinicians, which demonstrate the power of innovative biomaterial technologies and their potential impact on health care.
We can all breathe easy (pun intended!) knowing that there are people like Drs. Hollister and Seifalian, as well as countless others developing novel biomaterial constructs that can save lives.