Scientists claim to have developed a new technique for sperm preservation, which allows more functioning sperm to be recovered. The Chilean and German team reportedly used vitrification, which is currently used for cryopreserving ('freezing') eggs and embryos, to successfully preserve sperm.
After thawing, the sperm reportedly recovered with dramatically increased viability, and an 80 per cent motility rate. This is comparable to 30 to 40 per cent motility using the current method of slow-freezing sperm, which also damages the sperm cell membrane.
Lead author Professor Raul Sanchez from La Frontera University in Temuco, Chile, said: 'this work shows that we can preserve functional sperm via vitrification, which gives a greater chance of success for patients with low sperm counts. The other great advantage of this technique is that it can eliminate potential sources of infection such as AIDS (acquired immune deficiency syndrome) or hepatitis b, which are present in seminal plasma. It has the potential to allow HIV (human immunodeficiency virus) positive men to have children without worrying about transmitting the virus'.
Sperm vitrification involves removing the seminal fluid from around the sperm, resuspending them in sugar solution and then rapidly freezing them in liquid nitrogen. Removal of the seminal fluid, which is where HIV resides, could - the team say - give HIV-positive men the chance to father children without passing on the virus to mother or child.
But Dr Allan Pacey, Senior Lecturer in Andrology and an expert on sperm research at the University of Sheffield, told BioNews scientists: 'can already 'wash' sperm to remove HIV before freezing, so this claim is nothing new'.
The research was presented at the World Congress on Fertility and Sterility in Munich, which ran from 12th - 16th September.