Stem cells are one of the fascinating areas of biology today, with new experiments continually replacing our existing knowledge about the potential applications of stem cells.
Scientists have now been successful in manipulating rat sperm cells to behave like embryonic stem cells, which are capable of giving rise to various cell lineages such as a nerve cell, blood cell or a skin cell. In simple terms, the issue is all about making sperm cells pluripotent. The use of these cells in the treatment of diabetes and Parkinson's disease is still in infancy due to unresolved ethical issues stemming from the source of these cells - human embryos or mouse cells.
Ordinarily, when germ stem cells divide into two cells, one "daughter" cell differentiates to become a sperm while the other remains a stem cell. The study represents a remarkable breakthrough as the fate of the male germ cells that give rise to sperms have been altered. Surprisingly, the stem cells even retained their capacity to transform into sperms after they were transplanted back into rat testes.
One of the breakthroughs in this study was the development of a new culture medium to grow the cells and the incorporation of a tag, the green fluorescent protein to help enable easy identification of germ cells from a mixture.
The findings of the present study have valuable clinical implications. It can pave way for the development of male contraceptives and a refinement in the animal models used in the study of infertility. It can even serve as an ideal alternative to embryonic stem cells.
"The ability to manipulate male germ-line stem cells and get them to grow and self-renew is a major step," said Dr. Garbers, a Howard Hughes Medical Institute investigator at UT Southwestern.
The researchers have now focused their attention towards genetic manipulation of the derived rat cells so that it can be extrapolated to produce 'knock out mice' that can be used in studying health and behavioral effects related to the knocked off genes.
The next step is to determine whether human male germ-line stem cells can also be conferred immortality under artificial laboratory conditions. Perhaps, someday, it might be possible to correct genetic defects in humans such as cystic fibrosis in the near future.