Kidney \'grown\' in lab transplanted into animals

A kidney \"grown\" in the laboratory has been transplanted into animals where it started to produce urine, scientists said Monday. Similar techniques to make simple body parts have already been used in patients, but the kidney is one of the most complicated organs made so far. A study, in the journal Nature Medicine, showed the engineered kidneys were less effective than natural ones, the BBC reported. But regenerative medicine researchers said the field had huge promise. Kidneys filter the blood to remove waste and excess water. They are also the most in-demand organ for transplant, with long waiting lists. The researchers\' vision is to take an old kidney and strip it of all its old cells to leave a honeycomb-like scaffold. The kidney would then be rebuilt with cells taken from the patient. This would have two major advantages over current organ transplants. The tissue would match the patient, so they would not need a lifetime of drugs to suppress the immune system to prevent rejection, the scientists said. It would also vastly increase the number of organs available for transplant. Most organs which are offered are rejected, but they could be used as templates for new ones. Researchers at Massachusetts General Hospital have taken the first steps towards creating usable engineered kidneys. They took a rat kidney and used a detergent to wash away the old cells. The remaining web of proteins, or scaffold, looks just like a kidney, including an intricate network of blood vessels and drainage pipes. Grow-your-own organs might seem like a fantasy, but there are people walking around today with organs made in this way. A major breakthrough came in 2006 when bladders made from patients\' own cells were implanted. Grown windpipes have also been transplanted. In regenerative medicine there are four levels of complexity: flat structures such as skin; tubes such as blood vessels; hollow organs such as the bladder; and solid organs such as the kidney, heart and liver. The last group is the most difficult as they are complex organs containing many types of tissue. However, there have been early glimmers of success. Beating rat hearts have been produced, and grown lungs have been able to keep rats alive, if only for a short time. Growing solid organs is still in its infancy, but these animal studies provide an interesting window on what could be the future of organ transplants, the scientists said.