Ultraviolet filters, preservatives, and plasticizers may be responsible for fertility problems
A plethora of endocrine-disrupting chemicals interfere with human sperm function in a way that may have a negative impact on fertilization. These are the findings of a German - Danish team of researchers from the Center of Advanced European Studies and Research in Bonn, Germany, and the University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark. The work, which is published in EMBO reports, suggests that endocrine disruptors may contribute to widespread fertility problems in the Western world in a way that hitherto has not been recognized.
Endocrine disruptors are present in food, textiles, drugs, household, and personal-care products such as plastic bottles, toys, and cosmetics. Proving the deleterious effects of endocrine disruptors on human beings has been difficult due to a lack of suitable experimental systems.
The European Commission is currently reviewing its policy on endocrine-disrupting chemicals. Last year, their plans caused a debate between endocrinologists and a group of toxicologists over how to regulate these chemicals. “Our study provides scientific evidence to assist forming international rules and practices,” said the leader of the study, Timo Strünker, from the Center of Advanced European Studies and Research in Bonn, Germany.
“For the first time, we have shown a direct link between exposure to endocrine disrupting chemicals from industrial products and adverse effects on human sperm function,’’ said Niels E. Skakkebaek, professor and leader of the Danish team.
Hundreds to thousands of chemicals can be rapidly tested for their potential to interfere with human sperm function using the bioassay developed by the researchers. In this initial study, about one hundred chemicals were tested. Around one third, including ultraviolet (UV) filters like 4-methylbenzylidene camphor (4-MBC) used in some sunscreens, the anti-bacterial agent Triclosan used in toothpaste, and di-n-butylphthalate (DnBP), showed adverse actions.
The scientists looked at the impact of these chemicals on the CatSper ion channel, a calcium channel controlling sperm motility. They showed that endocrine disruptors – applied at concentrations measured in body fluids – directly open CatSper and, thereby, increase calcium levels in sperm, change their swimming behaviour, and trigger the release of digestive enzymes that help sperm to break through the egg coat. Moreover, endocrine disruptors render sperm less sensitive for progesterone and prostaglandins – two important hormones released by cells surrounding the egg. Finally, the authors noted that in low-dose mixtures, the chemicals cooperate to elevate calcium levels in sperm.
Altogether, the study indicates that endocrine disruptors might disturb the precisely coordinated sequence of events underlying fertilization in several ways: the chemicals might evoke changes in swimming behaviour at the wrong time and wrong place, hinder navigation of sperm towards the egg, and hamper penetration into the protective egg coat.
Stefan Hartmann | Max-Planck-Gesellschaft
A 'half-hearted' solution to one-sided heart failure
24.11.2017 | Boston Children's Hospital
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences