Thursday, June 14, 2012

Scientists grow new vein from girl's stem cell

LONDON: For the first time, scientists led by an Indian-origin researcher have successfully replaced a major blood vessel in a 10-year-old girl with a vein grown in a lab using her own stem cells. The pioneering transplant, published in The Lancet, marks a further advance in growing body parts in laboratory and offers hopes for patients who lack suitable veins for dialysis or bypass surgery. In the landmark research, a team from the University of Gothenburg in Sweden took a vein from a dead man, stripped of its own cells and then bathed in stem cells from the girl, who was suffering from portal vein obstruction. There was a "striking" improvement in her quality of life after the transplantation, Prof Suchitra Sumitran-Holgersson, who led the research, said. "This is the future for tissue engineering, where we can make tailor-made organs in the lab," Sumitran-Holgersson said. According to researchers, the hepatic portal vein, from which the girl was suffering, drains the blood from the intestines and spleen to the liver, and blockage can cause serious complications such as lethal variceal bleeding, enlarged spleen, developmental retardation, and even death. To date, attempts to restore portal blood flow using umbilical veins and artificial grafts to build a bridge around the blockage (called meso Rex bypass) have had mixed success. In the new study, the Swedish team took a 9cm segment of iliac (groin) vein from a live human donor and removed all living cells, leaving a tube consisting of just the protein scaffolding. This scaffolding was injected with stem cells obtained from the girl's own bone marrow. Two weeks after seeding, the graft was re-implanted during a meso Rex bypass procedure. The recipient had no complications from the operation and the procedure immediately restored normal blood flow. In the year following the operation the girl gained good height and weight. But a year after the procedure, decreased portal blood flow was noted and a narrowing of the graft required a second stem cell-based graft to be done. Since, the girl has remained well and is able to take long distance walks. Importantly, she has not developed anti-donor antibodies despite not taking immuno suppressive drugs, the team noted. "The new stem-cells derived graft resulted not only in good blood flow rates and normal laboratory test values but also, in strikingly improved quality of life for the patient, the researches concluded. "The work also establishes the feasibility and safety of a novel paradigm for treatment, in cases of venous insufficiency, obstructed veins or inadequate autologous veins. Furthermore our work opens interesting new areas of research, including trying to reproduce arteries for surgical use in patients with arteriovenous fistulas for dialysis [a type of vascular access for dialysis] or coronary bypass surgery," they noted. Commenting on the research, Martin Birchall and George Hamilton from University College London said: "The young girl in this report was spared the trauma of having veins harvested from the deep neck or leg with the associated risk of lower limb disorders, and avoided the need for a liver or multivisceral transplantation." But they cautioned the technique now needed to be tested in clinical trials and developed into a straightforward quality-controlled production process.

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