Fertility breakthrough - scientists grow sperm

JAPANESE scientists have successfully grown mice sperm and it's only a matter of time before they can cultivate the human variety.

Sperm

FOR men who've suffered the anguish of infertility, a medical miracle may be on the horizon.

Scientists have recently grown sperm in a lab, raising hopes for infertile men and boys with cancer who are treated with chemotherapy. Japanese researchers took tissue from the testes of baby mice and retrieved sperm even after the tissue had been frozen, suggesting that boys - who only have immature sperm cells in their testes - could freeze testicular tissue for use later in life.

But Australian fertility experts caution that despite the encouraging breakthrough, human sperm cultivation could be at least a decade away.

Male problems account for up to half of the number of infertility cases seen at IVF clinics. Sometimes the male has a low sperm count, the sperm have poor mobility or in more unusual cases, men produce no sperm at all.

Melbourne andrologist Professor Rob McLachlan from the Prince Henry Institute of Medical Research says male infertility is common: "Happily, in the last 20 years or so the technology to achieve pregnancy with men with fertility problems has developed very well. A lot of these guys previously wouldn't have had any chance at all."

It's for men who make no sperm at all that the latest research may prove helpful.

"The ability to convert the cells in the testes to go into a production line that produces sperm is a major breakthrough for a small group of these men," says Professor Michael Chapman, a senior IVF specialist at IVF Australia.

He estimates less than 5 per cent of all male fertility problems would benefit from the research, published last month in the journal Nature. The mice involved went on to have pups through IVF using the cultivated sperm. Boys undergoing chemotherapy or radiotherapy may also benefit if the results can be replicated in humans. For most men who don't produce any sperm, the cause is genetic and their only option currently is to use donor sperm or adopt.

"It's devastating. Women cry when I give them bad news but to see men cry is very traumatic," Professor Chapman says. Professor McLachlan adds: "For some men, [children] are the thing they want more than anything else in the world and the prospect of having it denied is terribly, profoundly upsetting for them."

He says people will always prefer to use their own sperm and microinjection technology means just one sperm per egg is needed. Luckily, sperm donors are easier to find than egg donors because the process is far less taxing. Professor McLachlan is concerned growing human cells could result in adverse reactions, though. "You may be able to force the issue in the lab but you don't know about the safety," he says.

"I'd want to see many, many generations of safety research in animals before doing this in humans. My concern is that if it almost works and you end up with a birth defect."

Monash IVF international medical director Professor Gab Kovacs says sperm and egg each have 23 chromosomes and combine at conception to make the 46 in each of our body cells. So sperm cells can't be cultivated from just any stem cell in the body.

He says the most common infertility problems in men involve sperm quality.

Things to look for, he says, are in the concentration; how many sperm per millilitre of semen, movement and the way they look: "The abnormality can be any one of those or a combination of all."

What causes male infertility?

- Sperm production problems: Low sperm counts and the sperm that are made don't work properly. Two-thirds of infertile men have sperm production problems.

- Blockages: Can cause complete lack of sperm in ejaculated semen. This is the second most common cause of male infertility.

- Sperm antibodies: Can reduce sperm movement and block the egg binding needed for fertilisation. One in every 16 infertile men has sperm antibodies.

- Sexual problems: Not common but an issue.

- Hormonal problems: Low testosterone levels and a failure of the testes to produce sperm affect about one in 100 infertile men.

- Other issues: Things that can affect male fertility include cigarette smoking, alcohol, STDs, heat stress from tight underwear, anabolic steroids and exposure to harmful chemicals.

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