Cloning mice from skin stem cells (2/15/2007)

Scientists from Rockefeller University and the Howard Hughes Medical Institute have cloned healthy mice from skin cells for the first time.

Cloning animals using the Somatic Cell Nuclear Transfer (SCNT), though it works occasionally is often only achieved through several failures. The process first developed by Ian Wilmut, who cloned dolly the sheep, involves taking an embryo and removing its nucleus. They then insert the genetic material from the animal they want to clone back into the empty embryo. Giving the embryo a brief electric shock starts the cellular division, and with a bit of luck will develop into an identical clone to the original.

It took 276 tries for Dr. Wilmut to successfully clone Dolly. All of the others died before maturity. Dolly also died young, from a genetic disorder similar to arthritis.

The new technique uses skin stem cells instead of normal cells. In this study, the success rate was only 1.6% using skin cells from female mice and 5.4% using cells from male mice. Compared to success rate of Dolly, 0.3%, it's a huge step forward.

The researchers used a type of stem cell found in the skin, called keratinocytes, which are attractive to scientists because they are easily harvested. The keratinocytes were found in hair follicles lying beneath the skin and are involved in hair growth and in repairing skin wounds.

The hope is that if researchers can overcome the current technical hurdles of making human embryonic stem cells by nuclear cloning, it may be possible one day to generate tailor made embryonic stem cells from a patient's skin stem cells.

Instead of allowing the embryo to mature and eventually grow into a human, they will halt the division within the first five days. Once the process has been halted they will extract the embryonic stem cells from the embryo.

Researchers are hoping that embryonic stem cells could one day be a useful treatment for many conditions such as Alzheimer's and heart disease. Several clinical trials are already attempting to treat heart disease, brain damage, and replacing skin on burn victims using varying types of stem cells. Several other less critical problems like, cartilage damage and tooth replacement, are also being put through trials.

Not all stem cells are created equal though. Several scientists have proven that embryonic stem cells are the best cells to use because the have the ability to differentiate into more types of tissues than other types of stem cells.

Post Comments: