Test tube sperm an insight to fertility

LONDON: A team of British scientists claimed yesterday to have created human sperm using embryonic stem cells in a medical first they say will lead to a better understanding of fertility.

Researchers led by Karim Nayernia at Newcastle University and the North East England Stem Cell Institute developed a technique that allows the creation of human sperm in the laboratory.

They stressed that the sperm, developed from stem cells with XY chromosomes (male), would not be used for fertility treatment, as this is prohibited by British law and in any case is not their main interest.

"This is an important development as it will allow researchers to study in detail how sperm forms and lead to a better understanding of infertility in men - why it happens and what is causing it," Professor Nayernia said.

"This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own."

He said more investigation was needed to decide whether the so-called in-vitro derived sperm could be used as a fertility treatment, for example, for boys who became infertile after receiving chemotherapy for cancer.

While such a treatment would not be likely to be developed for at least a decade, Professor Nayernia said legislation should be put in place "sooner rather than later" to allow the technique to be licensed.

The team's work involved developing stem cells that had XY chromosomes into germline cells - cells that can can pass their genetic material to future generations.

These were then prompted to complete meiosis, or cell division, which produced "fully mature, functional sperm".

Stem cells are immature cells that can develop into different cell types.

The scientists tried to develop cells with XX chromosomes (female) in the same way but they did not progress beyond early stage sperm, called spermatagonia. The team concluded that the genes on a Y chromosome are essential for sperm maturation.

The research, published in the journal Stem Cells and Development, could lead to a better understanding of how genetic diseases are passed on.

HIV is found to be fast

Human immunodeficiency virus, once considered a slow if stealthy invader, actually works incredibly fast at disarming key immune fighters in the body, scientists at Duke University and UNC-Chapel Hill reported Monday.

What's more, HIV strikes an army of immune cells that scientists previously believed were less vulnerable early on.

The findings, reported in the online journal PloS Medicine, provide a better understanding of how to develop a vaccine to protect against the virus that causes AIDS. It newly infects an estimated 56,300 people a year in the United States.

"It's very helpful to us to know exactly what's going on" with the immune system, said Dr. Barton Haynes, who is an immunologist at Duke, director of the Center for HIV/AIDS Vaccine Immunology and the senior author of the study.

The insight was gained using technology pioneered at UNC-Chapel Hill that detects the virus within days of infection, rather than months. North Carolina began using the early detection methods at public health clinics, and a group of newly diagnosed patients agreed to participate in a study of how the immune system is affected at early stages.

Findings from these patients showed that three lines of attack by the immune system are quickly neutralized by HIV.

First, the virus wipes out the nurturing centers of the gut that harbor so-called B cells, infection fighters that originate in the bone marrow and congregate in areas of the small intestine.

In addition, HIV triggers a sort of smoke screen that provides it cover while the B cells spring into action, armed to fight every threat imaginable but unable to effectively target the real danger.

Finally, the virus also wipes out helper B cells, which are necessary for an effective response.

"To everyone's surprise, they found all this damage and cell death," said Dr. David Margolis, an AIDS researcher at UNC-CH and one of the study authors. He said the surprise was both in the timing of the onslaught, and in the target.

For years, HIV researchers focused on a different immune fighter -- T cells, killer cells formed not in the bone marrow, but in the thymus gland. HIV was known to take over T cells, destroying their ability to fight infections. But even with the new insights, Haynes said, scientists have a formidable task developing a vaccine.

"It would have to be different than any other vaccine made," Haynes said.