Just as the wrinkles on your face denote age, your testicles also have their own way of showing their age, and it has nothing to do with their wrinkliness.
As testicles age, DNA incurs damage and sperm loses some of its function; we know that much, but why it happens is less understood. Researchers in China may have found a molecule that speeds up testicular aging.
According to a study published in the Journal of Molecular Cell Biology, scientists at the Chinese Academy of Sciences and the Naval Medical University analyzed over 10,000 cell nuclei from young and old donors. Unlike ovaries, which run on a strict, finite egg timer, testicles operate a self-renewing stem cell bank that keeps the factory running well into a guy’s senior years.
But around age 45, while still functional, the machinery starts to show its age.
Scientists Found a Surprising Connection Between Aging Testicles and a Little-Known Protein
Researchers say testicular aging comes down to a communication breakdown between two vital parts of the process: Leydig cells, which pump out testosterone, and Sertoli cells, which support developing sperm. In young testicles, these two are in constant communication. In older testicles, the pair have developed the kind of communication issues that usually lead to couples therapy.
Sertoli cells start cranking out massive amounts of a protein called WLS, the villain of the story, which plays a big role in pathways run by a transporter called Wnt, essentially the master switchboard regulating cell survival, renewal, and metabolism.
When researchers artificially cranked up WLS levels in lab-cultured cells, those cells rapidly aged, proving WLS is actively aging testicles.
One major caveat is that the team examined only four human donors, since high-quality tissue samples are hard to come by. They’re going to need a lot more samples to confirm their findings, but the team has already made big strides just in identifying WLS as the source of testicle aging, which is knowledge that may one day help an entirely different team of researchers develop a fertility treatment for aging men.
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