In a first-of-its kind study, Scientists in China have grown new ears for five children with a congenital defect in one ear (Microtia).
Using Chrondrocytes (cartilage cells) collected from the affected ears, the Scientists were able to grow new ear-shaped cartilage, based on 3-D models from the children’s healthy ears.
According to a study published in EBioMedicine, the newly formed ears were transferred to the children, with ear reconstruction done.
“We were able to successfully design, fabricate, and regenerate patient-specific external ears”, with a follow-up of 30 months.
“Nevertheless, further efforts remain necessary to eventually translate this prototype work into routine clinical practices”, the researchers iterated.
“In the future, long-term (up to 5 years) follow-up of the cartilage properties and clinical outcomes … will be essential”.
Understanding Microtia
Microtia is a birth defect resulting from an underdeveloped pinna (external ear), which may cause hearing impairment.
Affecting about one in every 5,000 live births (depend on ethnicity), is mostly prevalent in Hispanic, Asian, Native American and Andean communities
Treatment for Microtia includes reconstructive surgery by either generating an ear from the patient’s rib cartilage or sculpting an artificial plastic-made ear that is attached to the body.
A Professor of biomedical engineering and mechanical and aerospace engineering at Cornell University in Ithaca, New York, Lawrence Bonassar,said “the delivery of shaped cartilage for the reconstruction of Microtia has been a goal of the tissue engineering community for more than two decades”.
Speaking on the new study, he asserts that “this work clearly shows tissue engineering approaches for reconstruction of the ear and other cartilaginous tissues will become a clinical reality very soon. The aesthetics of the tissue produced are on par with what can be expected of the best clinical procedures at the present time”.
A new approach?
According to Dr. Tessa Hadlock, Chief of facial plastic and reconstructive surgery at Massachusetts Eye and Ear in Boston, the approach used in the new study is nothing new as other scientists have had the same idea, only this time, the idea came into fruition.
In 1997, a group of researchers grew tissue-engineered cartilage in the form of a human ear using chondrocytes and implanted it on the backs of mice.
“Surgeons have been toying with the idea of removing cartilage tissue from a patient and distilling that tissue into individual cellular components and then expanding those cellular components. In other words, having the cells divide so you have a bigger piece or more cells to make a new part with,” Hadlock said.
“For many years, we have tried to harvest cells from people and expand those cells on polymer to grow kind of a new structure, and we’ve done it in animals for a long time, and it also was FDA-approved for some studies here in the United States where we were trying to fix problems with the bladder in a condition called vesicoureteral reflux”
As for the new study, “the thing that is novel about this is that for the first time, they have done it in a series of five patients, and they have good long-term followup that shows the results of the ears that were grown from that harvested cartilage,” she added.
Challenges faced
Although the researchers described the results so far as “a significant breakthrough” in the clinical application of engineering human ear-shaped cartilage, the approach comes with several limitations.
“The part about this work that is dangerous is when you remove cells from someone’s body and you grow them in culture, you have to apply stimulating compounds to the cells to get them to divide”.
“When you apply those stimulating compounds, you are running the risk of allowing those cells to go haywire from a division standpoint. It’s another way of saying that you can actually create like a cancerous type of uncontrolled growth,” Hadlock added.
”Another limitation is on how the researchers used the children’s own chondrocytes, the cartilage cells within their ears, even though their ears had been diagnosed with Microtia”.
“Because the ear is not normal, they in and of themselves may be diseased. They may be different than a totally healthy chondrocyte. That’s something about which we don’t have enough information.”
The study was carried out on a 6-year-old girl, a 9-year-old girl, an 8-year-old girl, a 7-year-old boy and a 7-year-old girl, all with unilateral microtia.
