Germana Carillo The reasons why PFAS cause a decrease in fertility have been discovered: they bind to a sperm protein, modifying its structure and preventing it from binding to its homologue in the oocyte
Recent research elucidates the ways in which PFAS impinge on human fertility. In an apparent specific attachment, these chemicals attach to a certain protein on the membrane of the sperm cell known as “Izumo-1“. This interaction alters the shape of the protein such that it cannot bind with its counterpart on the egg’s membrane, a protein called the “Juno” protein. This fact leads to the major reduction of fertility by PFAS.
Research behind the findings
This pioneering work came from Professor Carlo Foresta, president of the Foresta Foundation ETS, with the collaboration of Professor Alberto Ferlin of the Department of Medicine at the University of Padua and Professor Diego Guidolin of the Department of Neurosciences.
The role of “Izumo-1” and “Juno
As the scientists said, “Izumo-1” and “Juno” are the key proteins during fertilization. They are a kind of bridge to help in the recognition and fusion of sperm and egg cells. In the absence of such proteins, reproduction cannot proceed.
Their interaction is crucial to the successful fertilization of an egg by a sperm cell. After the binding of these proteins, membranes of the sperm and egg fuse and allow the nucleus of the sperm to enter into the egg, causing fertilization.
“The results obtained are crucial for understanding the mechanisms leading to infertility in populations exposed to PFAS,” says Professor Carlo Foresta.Past studies had pointed out several defects in the sperm, resulting from PFAS exposure, such as lower sperm counts and motility. But the most recent study shows that if, somehow, a sperm reaches an egg-either via a semen ejaculate or through IVF-the sperm’s ability to actually fertilize the egg remains low due to PFAS’ attachment to the important “Izumo-1” protein.
PFAS: “forever chemicals” in focus
Greater awareness of PFAS has certainly happened in recent years. Known by the nickname “forever chemicals,” they’ve been widely used because of their resistance to water, grease, and stains; those very same characteristics make it renowned for persistence both in the environment and in the body because it does not degrade within a specific period.
PFAS accumulate in water and soil and can enter the human body through contaminated food or contact with treated objects. Many studies have already demonstrated that exposure to these chemicals creates severe health risks, including liver disease and immune system disorders. This new Italian study adds another critical layer to our understanding of their impact.
