WEDNESDAY, June 3, 2009 (HealthDay News) -- Using cells from pig ears and bone marrow, researchers in China generated a type of stem cell capable of developing into any type of cell in the body.
This is the first time researchers have created pluripotent stem cells using cells from a hooved animal that weren't derived from sperm or eggs. Like embryonic stem cells, pluripotent stem cells can differentiate into other types of cells.
The researchers hope their discovery will move scientists closer to genetically engineering pigs for organ transplants for humans and developing pigs that are resistant to diseases such as swine flu.
The study findings were published online June 3 in the Journal of Molecular Cell Biology.
"The pig species is significantly similar to humans in its form and function, and the organ dimensions are largely similar to human organs," lead study author Lei Xiao, who heads the stem-cell lab at the Shanghai Institute of Biochemistry and Cell Biology, said in a news release from the journal. "We could use embryonic stem cells or induced stem cells to modify the immune-related genes in the pig to make the pig organ compatible to the human immune system. Then we could use these pigs as organ donors to provide organs for patients that won't trigger an adverse reaction from the patient's own immune system."
Pig pluripotent stem-cell lines could also be used to help study human genetic diseases, Xiao noted.
"Many human diseases, such as diabetes, are caused by a disorder of gene expression," Xiao said in the news release. "We could modify the pig gene in the stem cells and generate pigs carrying the same gene disorder so that they would have a similar syndrome to that seen in human patients. Then it would be possible to use the pig model to develop therapies to treat the disease."
To induce the pluripotent cells, researchers used a virus to introduce transcription factors, which reprogram cells, to cells taken from a pig's ear and bone marrow. After the introduction of transcription factors, the cells developed in the lab into colonies of embryonic-like stem cells.
Further tests confirmed the cells were capable of differentiating into the cell types that make up the three layers in an embryo -- endoderm, mesoderm and ectoderm -- a characteristic of all embryonic stem cells.
The discovery will make it easier for researchers to develop embryonic stem cells from embryos of pigs and other hooved animals, known as ungulates, according to the study.
Although treatments in humans are several years away or more, Xiao said his next research will be using the induced pluripotent cells to generate gene-modified pigs that could provide organs for patients or aid in disease resistance.
The induced pluripotent cells could either be used to transfer an additional bit of genetic material (such as a piece of human DNA) into the pig's genome or to prevent a particular gene from functioning.
"This research is very exciting because it represents the first rigorous demonstration of the establishment of pluripotent stem cell in ungulate species, which will open up interesting opportunities for creating precise, gene-modified animals for research, therapeutic and agricultural purposes," said Dangsheng Li, the journal's editor-in-chief, in the news release.
For more on stem cells, visit the U.S. National Institutes of Health's resource for stem cell research.