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Patients' own cells used to create new organs for transplantation

Replacement vaginas, nostrils grown in lab from patients’ own cells advance transplant science

AP, Reuters

Two new studies describe the latest achievements in growing body parts in a lab and transplanting them into people, this time with nostrils and vaginas.

Windpipes, bladders, blood vessels and other structures have previously been created in part from a patient’s own cells and then implanted. Eventually, scientists hope to tackle more complicated things like lungs and kidneys with this strategy, which is aimed at avoiding rejection of transplanted organs.

The latest experiments were published online Friday in the journal The Lancet.

“They both show that by using fairly simple tissue engineering techniques, you can get real tissue forming where it’s supposed to,” said Dr. Martin Birchall, of The Ear Institute at University College London, who co-authored an accompanying commentary. He said the simple methods could be useful for making other body parts, including joint cartilage, bowels and the esophagus.

One experiment involved four teenage girls in Mexico who were born without vaginas because of a rare disorder. Currently, surgeons use tissue grafts to create vaginas for such patients, but that method carries a risk of complications.

The experimental results were reported by Dr. Anthony Atala, director of Wake Forest Baptist Medical Center’s Institute for Regenerative Medicine in North Carolina, with researchers there and at the Metropolitan Autonomous University in Mexico City.

Atala said the procedure may also prove useful for replacing vaginas removed because of cancer, and repairing or replacing the organ after an injury.

For the experiment, researchers took a tissue sample less than half the size of a postage stamp from the patients’ genitals. They multiplied cells from this tissue in the lab, seeded them onto a biodegradable scaffold and molded it into the right size and shape for each patient before implantation.

The first surgery was done in 2005, and the Lancet report provides a followup of the patients for an average of nearly seven years. The women report normal levels of sexual functioning, without any long-term complications.

The tests showed 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.

“By the six-month time point, you couldn’t tell the difference between engineered organ and the normal organ,” Atala said.

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 Atala.

The four 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, said Atala.

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. In prior studies, Atala’s team has used the approach to make replacement bladders and urine tubes or urethras in young boys.

In the other experiment, Swiss scientists built new outer nostrils for five patients who had skin cancer on their noses. When surgeons removed the tumor, they also took a tiny bit of nose cartilage. They grew the cells for four weeks in the lab to make a small flap. That was then implanted onto their nose and coveredwith skin from their foreheads.

Normally, cartilage is taken from the patient’s ear or ribs to recreate the nostril.

Ivan Martin of University Hospital Basel, the study’s senior author, said none of the patients reported any side effects by one year after surgery, and all were satisfied with their new nostrils.

“Now that we have demonstrated this is safe and feasible, we can use it for more complicated clinical needs,” he said, adding the same approach is being tested to supply knee cartilage. He said scientists were slowly gaining more expertise, but predicted it could take another couple of decades before the process becomes mainstream.

“It’s not a trivial thing to engineer a functional tissue,” he said.