A new study funded by a $3.25 million Department of Defense grant is launching research to address infertility in men with spinal cord injuries (SCI). Dr. Emad Ibrahim, director of the Male Fertility Research Program at the University of Miami Miller School of Medicine, will lead a four-year study testing an oral medication designed to improve sperm quality in these men.
Infertility Is Common Among Men with Spinal Cord Injuries
Spinal cord injuries mainly affect men, who make up nearly 80% of SCI cases. The average age of these men is about 43, a stage in life when many are planning to start or grow their families. Unfortunately, most men with SCI face erectile dysfunction and an inability to ejaculate. These issues often lead to infertility, caused by a low sperm count or mostly nonviable sperm.
“Many of these men either cannot produce enough sperm, or most of the sperm they do produce are dead,” explained Dr. Ibrahim.
Since joining the Miller School in 2004, Dr. Ibrahim and his team have dedicated their research to understanding the fertility challenges faced by men with SCI.
How Spinal Cord Injury Harms Sperm Quality
Research shows that spinal cord injuries trigger inflammation in the body. This inflammation causes the release of toxic molecules called cytokines, which damage sperm cells.
“These cytokines damage sperm, reducing their quality and viability,” Dr. Ibrahim said.
Further studies revealed that a protein complex called the inflammasome activates these harmful cytokines, making the damage worse.
Probenecid: A Safe, Affordable Drug with Potential Fertility Benefits
Working with neuroscientists from The Miami Project, Dr. Ibrahim’s team found that probenecid — a long-used medication for gout — can block the inflammasome. This reduces the levels of toxic cytokines and protects sperm cells.
“Probenecid prevents the activation of this harmful cascade,” said Dr. Ibrahim. “It is safe, effective, and inexpensive.”
A small 2018 study showed that men with SCI who took probenecid for one month had better sperm count and quality. This was the first evidence that an oral drug could help improve fertility in men with spinal cord injuries.
A Larger Clinical Trial to Confirm Benefits
Building on these promising results, Dr. Ibrahim secured a major grant to run a larger clinical trial. About 100 men with SCI will participate in this four-year study. They will receive either probenecid or a placebo for three months.
“We will measure sperm quantity and quality, including DNA damage, which is common in men with spinal cord injury,” Dr. Ibrahim said. “We will test sperm before and after treatment to see if probenecid improves reproductive potential.”
Hope for Improved Quality of Life
Infertility severely affects the quality of life for men with spinal cord injuries, noted Dr. Ranjith Ramasamy, director of reproductive urology at the Desai Sethi Urology Institute.
Currently, the only way for these men to father children is through expensive in vitro fertilization (IVF), which is not always successful. A low-cost, safe medication like probenecid could offer couples simpler, less invasive options such as insemination.
“We are proud to support Dr. Ibrahim’s research,” said Dr. Ramasamy. “This funding could lead to new therapies that help men with spinal cord injuries become fathers.”
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