Follow-up tests show the new vaginas are indistinguishable from
the women's own tissue and have grown in size as the young women,
who got the implants as teens, matured.
All four of the women are now sexually active and report normal
vaginal function. Two of the four, who were born with a working
uterus but no vagina, now menstruate normally.
It is not yet clear whether these women can bear children, but
because they are menstruating, it suggests their ovaries are
working, so it may be possible, said Dr Anthony Atala, director of
Wake Forest Baptist Medical Center's Institute for Regenerative
Medicine in North Carolina.
The feat, which Atala and colleagues in Mexico describe in the
journal the Lancet, is the latest demonstration from the growing
field of regenerative medicine, a discipline in which doctors take
advantage of the body's power to regrow and replace cells.
In prior studies, Atala's team has used the approach to make
replacement bladders and urine tubes or urethras in young boys.
Atala said the pilot study is the first to show that vaginal organs
custom-built in the lab using patients' own cells can be
successfully used in humans, offering a new option for women who
need reconstructive surgeries.
All four of the women in the study were born with
Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a rare genetic
condition in which the vagina and uterus are underdeveloped or
absent. Conventional treatment generally involves the use of grafts
made from intestinal tissue or from skin, but both tissues have
drawbacks, says Atala, a pediatric urologic surgeon at Wake Forest.
Intestinal tissue produces an excess of mucus, which can cause
problems with odor. Conventional skin, meanwhile, can collapse.
Atala said women with this condition usually seek treatment as
teenagers. "They can't menstruate, especially when they have a
severe defect where they don't have an opening," he said. This can
cause abdominal pain as menstrual blood collects in the abdomen. "It
has nowhere else to go," he added.
Girls in the study were aged 13 and 18 at the time of the surgeries,
which were performed between June 2005 and October 2008.
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The researchers started off by collecting a small amount of cells
from genital tissue and grew two types of cells in the lab: muscle
cells and epithelial cells, a type of cell that lines body cavities.
About four weeks later, the team started applying layers of the
cells onto a scaffold made of collagen, a material that can be
absorbed by the body. They then shaped the organ to fit each
patient's anatomy, and placed it in an incubator.
A week later, the team created a cavity in the body and surgically
attached the vaginal implants to existing reproductive organs. Once
implanted, nerves and blood vessels formed to feed the new organ,
and new cells eventually replaced the scaffolding as it was absorbed
by the body.
"By the six-month time point, you couldn't tell the difference
between engineered organ and the normal organ," Atala said.
The team continued to monitor the young women, taking tissue
biopsies, MRI scans and internal exams, for up to eight years from
the initial implants.
All of these tests showed the engineered vaginas "were similar in
makeup and function to native tissue," said Atlantida-Raya Rivera,
director of the HIMFG Tissue Engineering Laboratory at the
Metropolitan Autonomous University in Mexico City, where the
surgeries were performed.
Professor Martin Birchall of UCL Ear Institute in London, who wrote
a commentary in the same journal, said the findings address some
important questions about tissue-engineering, including whether
tissue will grow as patients grow and whether an organ as large as
the vagina can develop blood vessels when implanted in the body.
(Editing by Michele Gershberg and Matthew Lewis)
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