Japanese researchers solve common form of male infertility


Staff Writer

Researchers have found a solution for a common form of male infertility. Nonobstructive azoospermia is a condition in which sperm do not grow to maturity.

Japanese researchers have now reported a way to extract immature sperm from the testicle and use it for in vitro fertilization. They are using it successfully at a clinic in Kitakyushu.

The team was headed by Atsushi Tanaka, founder of the clinic, Saint Mother Hospital. The researchers say it resulted in 112 births between September 2011 and December 2014.

The clinic is thought to be the first carrying out such treatment successfully.

The team found a way to identify round spermatids, sperm cells that have not matured. This is difficult.

“It took us about a decade to find a way to differentiate the cells, which was one of the main reasons why this treatment was unsuccessful,” said Tanaka, who specializes in both male and female infertility.

“Such a method is possible using chromosomal analysis. It enables us to select round spermatid cells with a near-perfect accuracy.”

Until now, men with nonobstructive azoospermia have been considered fundamentally sterile, with conception possible only with the use of donated sperm.

Men with obstructive azoospermia, meanwhile, usually have the ability to produce healthy sperm which cannot pass through the spermatic duct.

The work was published in the Nov. 24 issue of U.S.-based science journal Proceedings of the National Academy of Sciences.

Of the 112 births via the method, 14 were from men diagnosed with nonobstructive azoospermia at other medical institutions after a biopsy. In each case, the man was told use of a sperm donor would be the only way to conceive.

Tanaka said his group’s study suggest that viable spermatid cells can be found in 30 to 40 percent of patients with nonobstructive azoospermia who have not produced mature sperm.

Azoospermia is said to occur in 1 percent of men. Of sufferers, 94 percent of them are diagnosed with nonobstructive azoospermia. The World Health Organization says 10 percent of all infertile men have the nonobstructive condition.