North scientists offer hope for infertile couples
Jul 8 2009 by Helen Rae, The Journal
Team developed new method
THE Newcastle University team developed a method for establishing early stage sperm from human embryonic stem cells.
The embryonic stem cells were cultured in a new medium containing vitamin A derivative (retinoic acid), in a technique established by the team. Based on this technique, the cells differentiated into germline stem cells.
These expressed a protein which was stained with a green fluorescent marker and they were separated out by FACSTM (Fluorescence-activated cell sorting) using a laser.
After further differentiation, these in vitro derived germline stem cells expressed markers which are specific to primordial germ cells, spermatogonial stem cells, meiotic (spermatocytes) and post meiotic germ cells (spermatids and sperm).
These results indicated maturation of the primordial germ cells to haploid male gametes – called IVD sperm – characterised by containing half a chromosome set (23 chromosomes).
Prof Nayernia said: "In the lab, we prompted embryonic stem cells like these, to develop into many different cell types.
"A temporary green marker stained those which had the characteristics of early sperm and they were separated out by laser.
"Growing in a medium containing vitamin A derivative, these early stage sperm are called spermatagonia. We saw some of them later develop to form spermatocytes – where the chromosome set halves... And they then went on to form spermatid.
"In our research, some of these spermatid continued to grow, elongating and pushing out a tail which enabled it to move – forming the in vitro derived sperm or IVD sperm. They can be seen moving under the microscope in film from our original research project."
Cases can be cured
MORE and more men aged 50-65 are now attending fertility clinics, with men over 40 making up nearly a quarter of consultations.
Up to half of all cases of infertility involve problems with the man. In fact, about 20% to 30% of the time, a man’s low fertility is the main obstacle to conception.
Causes of male infertility may include: low sperm count, sperm that are abnormally shaped or that don’t move correctly, undescended testicle or an underlying medical problem.
Sometimes the cause of male infertility cannot be identified. In these cases, there may be an underlying genetic problem.
More than one-half of cases of male infertility can be corrected.
