Research on stem cells as a cure for infertility has made considerable progress. In five years it should be possible to grow mature sperm from adult stem cells, says Dr.Karim Nayerina, noted Iranian-born biomedical scientist.
In July 2006, Dr. Nayernia, a professor of stem biology at the University of Newcastle upon Tyne reported that he and his team had successfully coaxed the embryonic stem cells of mice into becoming mature sperm. This sperm was successfully used to fertilize eggs, resulting in the live birth of seven mice. While six of the seven mice survived to adulthood, each mouse exhibited some variety of abnormal development, such as stunted growth and difficulty walking.
More recently, Dr. Nayernia has focused his research on the development of sperm cells from adult stem cells found in the bone marrow tissue of rats, rather than from embryonic stem cells. Dr. Nayernia and his team were able to cause the adult stem cells to undergo the first two of the three divisions required for these cells to become sperm cells.
While his team's inability to turn adult rat stem cells into fully mature sperm has solicited criticism and caution from the scientific community, Dr. Nayernia has proceeded to experiment with samples of stem cells taken from the bone marrow of human males.
The scientists added both vitamin A and proteins (both of which purportedly encourage the development of sperm) to the adult stem cells. The procedure showed promise as the human stem cells began to develop into sperm; however, these developing stem cells never reached full maturity.
While success with human adult stem cells has remained elusive, Dr. Nayernia remains optimistic about the culmination of his research with stem cells, embryonic and adult, mouse and human. He believes that the ability to use human adult stem cells to grow mature sperm and implant them into the infertile male's testes is no more than five years away.