March 8, 2011
Scientists from Wake Forest and from Mexico have collaborated to grow new, functional urethras for five boys in Mexico. The team is the first in the world to use patients' own cells to build tailor-made urinary tubes and successfully replace damaged tissue. Five boys, ages 10 to 14, had new urethras made using their own cells; three patients had injury due to trauma and two patients had previous urethra repairs that had failed.
The scientists isolated smooth muscle cells and endothelial cells from a small snip of tissue from each patient and grew the cells in the lab for 3-6 weeks. The cells were then used to coat a 3-dimensional scaffold shaped like a urethral tube and sized for each individual patient, made from the same material as used for dissolvable sutures. Senior investigator Dr. Anthony Atala of Wake Forest University School of Medicine said the process was "very much like baking a layer cake." According to Atala, with the engineered urinary tubes, "It's like they now just have their own urethras." He noted that similar techniques might be used for more complicated tubular structures in the body. Previously, Atala and his colleagues had created functional bladders for patients, using the patients' own cells, eliminating any possibility of transplant rejection.
The cell-coated scaffolds were incubated for seven days in the lab, allowing the cells to cover the entire surface area of the new urethral construct, and then surgically implanted into patients, replacing the damaged urethras. Engineered urethras were functional for at least a six-year follow-up period.
The results are published online in The Lancet.