US researchers make skin cells act as stem cells in mice

Three teams of researchers from Harvard University, California and Japan claim to have devised a method to produce embryonic stem cells without destroying embryos in mice and intend to apply the same to human cells without having women to donate eggs.

The research team, led by, Kevin Eggan (32) of the Harvard Stem Cell Institute took ordinary skin cells from mice and formatted them to act like embryonic cells. A new version of making copies of cells was used 11 years ago at the time of producing Dolly, the sheep.

According to the experts these embryonic cells (which are created after conception) might be useful in replacing damaged cells and missing tissues in humans and help in transplant therapies for curing people from diseases like paralysis, Alzheimer’s and Parkinson’s disease. But scientists are still investigating its use and are willing to wait for years to implement it.

Scientists tried to implement the nuclear transfer in humans using eggs donated by women but due to females not willing to donate eggs from their ovaries, the research couldn’t be carried forward.

Critics, including religious leaders, are against the use of human embryos in such a manner (extracting the cells by destruction of the embryo) and even the Bush government has denied funding for carrying forward such a research but the scientists believe that such criticism shall die down once they succeed to implement this technique in humans.

The journal, Nature, will publish three of the studies tomorrow and shall also include comments from Alan Colman of ES Cell International, a Singapore-based stem-cell company which says, “The findings may well revolutionize the field of human stem-cell research and remove ethical objections to such work”.

The assumptions regarding the technique (nuclear transfer) used to clone Dolly and 11 other species of animals was that the nucleus removed from one cell and inserted into another egg cell required the nucleus of the recipient cell to be removed so that the recipient egg cell follows the genetic features of the donor cell rather than the original.

Earlier the scientists believed that such a nucleus transfer could occur only in an unfertilized egg as said by Susan Fisher, acting director of the human embryonic stem cell program at the University of California, San Francisco.

But after a long period of research the colleagues devised a new method in which they temporarily halted the process of cell division (mitosis) by exposing the cells of a mouse egg to a drug after its fertilization. Then the neatly lined chromosomes were plucked out and replaced with another set from a skin cell of an adult mouse. This method enabled the scientists to create embryonic stem cells in the uterus of a foster mother to create pups. They also discovered that even defective embryos fertilized by more than one sperm could be used to create cell lines.

“It is difficult to predict whether the results from mice can be translated to humans, given all the differences between mouse and human embryos”, said Renee Reijo Pera, director of human embryonic stem cell research at Stanford University.

The other group of studies by scientists included converting mature tissue cells called fibroblasts from adult mice to an embryonic stage in which they could become any cell in the body after dosing them with a recipe of four growth factors.

"The reason that we embarked on these experiments was not to come up with a solution to those people who have objections to embryonic stem cell," Dr. Kevin Eggan said.

He added further, "All of us strongly agree with human embryonic stem cell research. These experiments were not motivated by a desire to find an end run around those issues."