An adult-sized ‘human’ ear has been grown on the back of a rat by researchers from Japan. Their findings might pave the way for human trials in around 5 years’ time; there might be hope for people with birth defects or disfigurements.
Growing human living tissue on this level is a feat that has mostly remained unprecedented. Back in the 90s, researchers had grown an ear made from cow cartilage on the back of a rat. Pictures of the latter can easily be dismissed as the result of Photoshop — but, it was very much real. On the other hand, no human tissue was involved at all. This is what makes the new study different.
Two decades away from the rat-with-an-ear-on-its-back experiment, scientists have come closer to the concept of growing replacements for human tissue damaged in one way or another. A team from the University of Tokyo and Kyoto University have successfully cultivated a human-stem-cell-derived living ear on a lab rat’s back. They say that human trials can start off in half a decade.
The team changed human cells into embryonic stem cell-like ones. These were turned into specialised cells from which cartilage is built. The resulting cells were then placed into an ear-shaped tubing that was later implanted underneath the skin of a rat — there, it grew for two months. The end ‘product’ was a rat with a ‘human’ ear on its back (the tube had dissolved in the preceding weeks).
These findings might be particularly relevant to the condition of patients of anotia and microtia which are characterised by absent and malformed ears respectively. This human-grown ear can be grafted (when cleared for human trials) into these patients.
Statistics say that 5 in every 10,000 live births constitute this type of case. Treatment for this does exist, but it is not the ideal. Patients often undergo reconstruction using cartilage from their ribs; this is complicated as it requires up to 5 surgeries for the grafting, which can sometimes unfortunately result in chest deformity. Another technique involves having a synthetic implant which is a less invasive method. The current treatment obviously has room for improvement.
The new study, therefore, brings hope for these patients, specially that experimenting on live animals is not perceived as a good way. Using human tissue obtained from stem cells is much less invasive as it needs only a small skin sample.