New advance in tissue engineering

September 04, 2017

The first step in engineering the replacement urethral segments was taking a small (one-half inch by one-half inch) bladder biopsy from each patient. From each sample, scientists isolated smooth muscle cells and endothelial cells, the cells that line blood vessels and other tubular structures. These cells were multiplied in the lab for three to six weeks and were then placed on a three-dimensional scaffold shaped like a urethral tube. Smooth muscle cells were placed on the outside of the scaffold and endothelial cells on the inside. The scaffolds, which were sized for each individual patient, were made of a biodegradable mesh material. After cell placement, the scaffolds were incubated for seven days - with the total time for construction ranging from four to seven weeks. By day six, all surface areas were completely covered with cells.

After incubation, the tubes were surgically implanted by removing the defective segment of the urethra and scar tissue and sewing the replacement tubes in place. Once in the body, the cells continued to expand and tissue formation began. Biopsies showed that the engineered urethras had normal layers of epithelial and smooth muscle within three months after implantation. Flow measurements, urine tests and patient questionnaires confirmed patient satisfaction as measured by lack of nighttime leaking, straining to urinate, and urinary tract infections - common symptoms when urethral tubes become narrowed.

Source: Wake Forest Institute for Regenerative Medicine