Foreseeing a time when a patient's own cells may be harvested, multiplied, and fashioned into a replacement organ, researchers in Boston have successfully transplanted laboratory grown bladders (肾) into six dogs.
For a century, physicians have replaced diseased or damaged bladders by removing sections of a person's intestines (肠子) and shaping them into a substitute bladder. While the procedure offers some relief to patients, complications often develop because nature designs intestinal tissue for a purpose-absorbing nutrients-other than holding waste liquid of the body. "You start absorbing stuff that should be removed," says Anthony Atala of the Children's Hospital in Boston.
Other physicians have turned to human-made materials to create artificial bladders, but those efforts have also run into problems. Consequently, to build a better bladder, Atala and his colleagues decided to employ the organ's own cells.
To turn the cells into an organ, the researchers first form plastic which can break down naturally into bladder-shaped shell. They then coat its outside and inside with layers of cells needed.
To test this strategy, Atala's group obtained bladder tissue from dogs and grew it into organs. After removing the dogs' bladders, the investigators implanted (移植) the artificial ones coming from the dogs' own cells. Within a month, the organs began to perform like normal bladders.
Within three months, the plastic shells had broken down naturally, and the implanted organs were hard to distinguish from natural ones. Blood vessels (血管) quickly grew into them. Moreover, nerves seem to form proper connections with the new organs, allowing the dogs to regain normal control of their bladders. Some dogs have had the artificial bladders for nearly a year without any problems.
While the bladders of dogs closely resemble those of people, Atala warns that more testing of this transplant strategy must occur before artificial bladders are ready for the clinic.