Some sunscreen ingredients may disrupt sperm cell function

http://www.eurekalert.org/pub_releases/2016-04/tes-ssi040116.php

Public Release: 1-Apr-2016
Some sunscreen ingredients may disrupt sperm cell function
The Endocrine Society

Many ultraviolet (UV)-filtering chemicals commonly used in sunscreens interfere with the function of human sperm cells, and some mimic the effect of the female hormone progesterone, a new study finds. Results of the Danish study will be presented Friday at the Endocrine Society's 98th annual meeting in Boston.

"These results are of concern and might explain in part why unexplained infertility is so prevalent," said the study's senior investigator, Niels Skakkebaek, MD, DMSc, a professor at the University of Copenhagen and a researcher at the Copenhagen University Hospital, Rigshospitalet.

Although the purpose of the chemical UV filters is to reduce the amount of the sun's UV rays getting through the skin by absorbing UV, some UV filters are rapidly absorbed through the skin, Skakkebaek said. UV filter chemicals reportedly have been found in human blood samples and in 95 percent of urine samples in the U.S., Denmark and other countries.

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The researchers found that 13, or 45 percent, of the 29 UV filters tested induced calcium ion influxes in the sperm cells, thus interfering with normal sperm cell function. "This effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens," Skakkebaek said.

Furthermore, nine of the 13 UV filters seem to induce this calcium ion influx by directly activating the CatSper channel, thereby mimicking the effect of progesterone. This finding suggests that these UV filters are endocrine disruptors, Skakkebaek said. In addition, several of the UV filters affected important sperm functions normally controlled via CatSper, such as sperm motility.

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Eight of the 13 UV filters that disrupted sperm cell function are approved for use in the U.S. They are avobenzone, homosalate, meradimate, octisalate (also known as octyl salicylate), octinoxate (or octyl methoxycinnamate), octocrylene, oxybenzone (also called benzophenone-3 or BP-3) and padimate O. These chemicals are common active ingredients in sunscreens as well as sunscreen-containing personal care products, such as makeup, moisturizers and lip balms.