Tokyo, Feb. 23 (Kyodo): Researchers in Japan have succeeded in cloning a human kidney by cultivating human stem cells extracted from adult bone marrow into rat embryos, team members said.
The development is expected to increase the possibility of expanding regenerative medicine to anatomically complicated organs such as the kidney and lung as a potential means to treat patients with disorders of those organs.
A report of the study, headed by Takashi Yokoo of the department of internal medicine and gene therapy at Jikei University School of Medicine in Japan, will be published in the online edition of US publication Proceedings of the National Academy of Sciences, dated March 1.
According to Yokoo, the team removed rat embryos from the uterus, implanted human stem cells &emdash; treated with neutrophic factor genes to help the organ development &emdash; into the area in the embryos where the kidneys were being generated and cultured the embryos in vitro.
Two days after the stem cell implantation, researchers extracted the kidney area from the embryos and, after incubating it for six days, discovered the development of nephrons, or an excretory unit of the kidney, and the surrounding interstitium.
The team members checked the genes and confirmed that they were developed from human bone marrow stem cells.
They then transplanted the kidney into the stomach of another rat and observed that it grew to about 150 milligrams in two weeks.
