Microtia is a congenital condition that occurs in about 1 in every 5,000-7,000 births. Due to an error during the first trimester, the pinna (external ear) does not develop completely or correctly. There are different grades of microtia, ranging from a slightly smaller pinna (grade I) to complete absence of the ear (grade IV).
This deformity can be repaired when the child is about eight years old by obtaining cartilage from the child’s ribs and molding it into a new ear, which will continue to grow throughout the child’s life, just like a natural ear. However, there are some significant drawbacks to the latter approach, because the ribs aren’t able to rebuild the cartilage that was taken and requires multiple surgeries. But according to new research, there could be another way.
A team of researchers from the Great Ormond Street Hospital in London have converted mesenchymal stem cells obtained from fat into cartilage; the results of which were published in the journal Nanomedicine. A small sample of the patient’s fat is taken from the abdomen and the stem cells are extracted. The adipose-derived stem cells (ACSs) are then spread out onto a scaffold that is shaped like a pinna and is induced into growing and differentiating into ear-shaped cartilage.
Growing cartilage this way has several advantages over the traditional method. Obviously, the child will not experience the surgery, scar, or loss of cartilage from the rib. Obtaining the adipose tissue is much less invasive. This technique also only requires one surgery, which is a clear advantage for the child and their worried parents.
This isn’t the first time that ACSs have been grown into features used for reconstruction. A new review in Stem Cells Translational Medicine has analyzed 13 cases where these cells were used to create cranio-maxillofacial bone. With follow-up times ranging from 1-4 years, 10 of the 13 patients had integrated the stem cell-derived bone with their natural bone. Of those that failed, two implants needed to be redone due to the type of containment mesh used. The third case deemed a failure (septum perforation) was because the patient had a nose-picking habit that was apparently too hard to give up.
The success of the hard tissue implants gives hope that the technique to convert ACSs into cartilage will have an easy time with the subsequent safety testing required before it will be used in clinical practice. The researchers are optimistic that this approach could revolutionize microtia reconstruction by only requiring one surgery. Of course, this technique could also be used for other deformities or injuries that result in the loss of an ear or nose.
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