The use of tissue-engineered bladders started in 1999, when Children's Hospital in Boston implanted it in nine children. Seven out of the nine children continued to do follow up examinations to ensure that the bladders were working properly. All tissue engineered bladders functioned perfectly. This medical breakthrough was one of the decade's more important discoveries as it allowed patients who had serious bladder problems to have a second chance at having a perfectly functioning, brand new bladder.
What Kind of Tissues Were Made into a Bladder?
Medical practitioners who performed the procedure on the nine children used the children's own tissue to create the bladders. The tissues, or cells, were taken from the patients who would be receiving the engineered bladders. In that way, the doctors could assure that the risk of rejection of the tissue was lowered and medication with immunosuppressive drugs could be avoided.
Biopsy of Tissue Material
Before creating a bladder based on the autologous tissue of the patient, a biopsy had to be done first. In the biopsy, a small sample was taken from the cells of the original bladder. Small samples were taken both from the urothelial cells and the cell of the outer muscle.
The Role of a Scaffold
A scaffold is biodegradable structure where the cells that have been isolated and grown are expanded to produce more cells that are seeded. The scaffold is in the shape of a mesh which is formed into a bladder shape. It is made of polyglycolic acid and collagen. Since it is biodegradable, the scaffold will melt once it and the analogous tissue that has been seeded into it are implanted to the patient. Every scaffold is created to fit the patient specifically. Cells that have been seeded into the scaffold will continue to grow, enough to be able to fill the scaffold and form into a bladder.
Implanting the Engineered Bladder
Once the tissue engineered bladder was ready for implant (approximately 7 to 8 weeks after biopsy), surgery was then carried out. During the procedure, the engineered bladder is enclosed in omental tissue, which is a highly vascular and fatty tissue located in the front of the intestines. The omental tissue coat is used in order to encourage the growth of blood vessels in the engineered bladder.
After the Implant
In the nine children implanted with engineered bladders, the scaffolds eventually dissolved as the scientists expected them to. After five years of continued follow up examinations, the results showed that the engineered tissues developed into bladders that were almost identical to the original, non-engineered bladders.