Adding a missing protein to infertile human sperm gives the sperm the ability to successfully fertilize an egg, a lab-based study reports.

The research, published in the journal Fertility and Sterility, shows that healthy sperm transfer a protein, PLC zeta (PLCz), to the egg upon fertilisation. PLCz is critical in egg activation, a process that initiates embryo development.

In some cases of male infertility, sperm with defective PLCz will fail to fertilise and activate eggs. Professor Anthony Lai, of Cardiff University's Institute of Molecular and Experimental Medicine, UK, who co-led the study, explained that his research team 'used human sperm PLCz to obtain the positive results that we had previously observed only in experiments with mice'.

'When an unfertilised egg is injected with human PLCz, it responds exactly as it should do at fertilisation', he continued, 'resulting in successful embryo development to the blastocyst stage, vital to pregnancy success'.

While these initial laboratory tests provide hope for future infertility treatments, Professor Lai and his colleagues are aware that additional work is needed before human application. 'This was a lab experiment and our method could not be used in a fertility clinic in exactly the same way', he said, adding that 'there is potential to translate this advance into humans'.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, who was not involved in the study, told the Daily Telegraph: 'I think this is very interesting research. It is exciting that they have got to this stage'.

According to the newspaper Dr Pacey estimates that faulty PLCz is likely to be the underlying cause of infertility for about 2,000 of the 50,000 couples who seek fertility treatment each year in the UK.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.