Research illuminates influences on male fertility

Key Points

Increasingly, genetics is changing the way urologists diagnose and treat problems related to male infertility. As lab findings become clinical realities, andrologists and general urologists alike are finding their daily practices changed by advances in our understanding of the human genome.

"It's the most rapidly moving field in urology, and a big part of it is not only diagnosing infertility, but also making molecular diagnoses about offspring from the male gamete," said Craig S. Niederberger, MD, chief of andrology at the University of Illinois, Chicago.

Recent research suggests that chromosome microarray analysis (CMA) may have vast potential to improve the ability of clinicians to detect submicroscopic chromosome defects in male infertility.

"This is a high-tech way of looking at a whole lot of genetic information," Dr. Niederberger said of CMA. "We can ascertain the quality of DNA and the quality of the genetic information in a way that may not be possible, even with high-resolution genetic karyotypes."

The link between DNA integrity and certain diseases, both in the man carrying the DNA and in his offspring, is becoming more apparent. For example, soon-to-be-released data suggest that men with male factor infertility have a higher risk of developing certain types of cancers. This may indicate a common genetic origin of infertility and cancer.

Similarly, patients with oligoasthenoteratozoospermia have been found to have abnormally high levels of sperm DNA damage, suggesting a link between infertility and problems with DNA integrity that may ultimately result in diseases like cancer.

Microsurgery

Microsurgical techniques for male fertility problems also continue to evolve. The relatively new technique of longitudinal intussusception vasoepididymostomy, which allows for a larger opening in the tubule, may allow more surgeons to use the procedure.

"We're getting some good, honest benchmarks on the efficacy of this technique, which allows us more effectively to counsel our patients on its use," Dr. Niederberger said. "They can make informed decisions on reconstructive surgery."

There was a time when men with higher levels of follicle-stimulating hormones (FSH) were almost automatically disqualified as candidates for microdissection testicular sperm extraction. But in men with nonobstructive azoospermia, at least, emerging evidence suggests that FSH levels should have no effect on the decision to perform sperm extraction.