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GEN News Highlights : Apr 11, 2014
Lab-Grown Vaginas a Success, Years after Patient Implantation
Vaginal organs engineered in the laboratory can be used successfully in human beings, say researchers. The researchers base this assertion on the results of follow-up visits by the first four implant recipients, young women who were aged 13–18 years at the time the engineered organs were surgically implanted.
The young women who received the implants had been born with a rare form of vaginal aplasia, Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. Each year after they received the vaginas, which had been engineered from their own cells, the young women provided the researchers with histories; agreed to physical examinations, vaginoscopies, serial tissue biopsies, and MRIs; and filled out Female Sexual Function questionnaires.
All this information, the researchers concluded, showed that “the engineered vaginal organs had a function within the normal range long term, with up to an eight-year follow-up to date.” The researchers added that the success of the implants provided “one more example of how regenerative medicine strategies can be applied to a variety of tissues and organs.”
The strategy used for growing the vaginas involved the application of cells to a biodegradable, three-dimensional scaffold. This strategy had been used earlier, but only on relatively small structures, such as urethras and replacement bladders. Nonetheless, work with smaller structures had demonstrated that once cell-seeded scaffolds are implanted in the body, nerves and blood vessels form and the cells expand and form tissue. At the same time the scaffolding material is being absorbed by the body, the cells lay down materials to form a permanent support structure—gradually replacing the engineered scaffold with a new organ.
This tissue engineering approach was developed by researchers led by Anthony Atala, M.D., director of Wake Forest Baptist Medical Center’s Institute for Regenerative Medicine. These researchers subsequently extended this technique to the creation of vaginal structures, as they explain in an article (“Tissue-engineered autologous vaginal organs in patients: a pilot cohort study”) published April 11 in the Lancet.
According to this article, the vaginal organ structures were engineered using muscle and epithelial cells from a small biopsy of each patient's external genitals. After the cells were extracted from the tissues, they were cultured, expanded, and then used to seed a biodegradable scaffold, which consisted of decellularized porcine intestinal tissue that had been hand-sewn into a vagina-like shape. Then, the scaffolds, which were tailor-made to fit each patient, were allowed to mature in an incubator in a facility approved for human-tissue manufacturing.
About five to six weeks after the biopsy, surgeons created a canal in the patient’s pelvis and sutured the scaffold to reproductive structures. Followup testing on the lab-engineered vaginas showed the margin between native tissue and the engineered segments was indistinguishable and that the scaffold had developed into tri-layer vaginal tissue.
In the article, the author wrote, “Yearly examination of tissue biopsy samples showed a similar phenotypic and histological make-up to native tissue. Serial MRIs and vaginoscopy confirmed organ patency long term. All patients are sexually active and have functional variables in the normal range for desire or arousal, lubrication, orgasm, satisfaction, and absence of pain.”
Current treatments for MRHK syndrome include dilation of existing tissue or reconstructive surgery to create new vaginal tissue. A variety of materials can be used to surgically construct a new vagina—from skin grafts to tissue that lines the abdominal cavity. However, these substitutes often lack a normal muscle layer and some patients can develop a narrowing or contracting of the vagina.
The researchers say that with conventional treatments, the overall complication rate is as high as 75% in pediatric patients, with the need for vaginal dilation due to narrowing being the most common complication. While the researchers are optimistic about the future clinical applications of their technique, they added that the current study is limited because of its size, and that it will be important to gain further clinical experience with the technique and to compare it with established surgical procedures.
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