Bisphenols and Male Reproductive Health

Bisphenols are organic industrial chemicals, widely used in the manufacture of plastic articles such as polyvinylchloride (PVC), polycarbonate plastics and epoxy resins. Currently, among these compounds, bisphenol A (BPA), which represents the first-choice plasticizer due to its cross-linking properties, is produced and used in the highest volumes worldwide. It is detectable in a variety of consumer, industrial and medical products, such as eye glass frames, cigarette filters, thermal receipts, flooring, medical devices, dental sealants, children's toys, food and drink containers, including baby bottles. Unfortunately, after polymerization, unbound monomers of BPA can leach into water or food products especially at high temperatures and with repeated use of plastic containers, making possible their dietary ingestion. Inhalation of indoor dust and dermal contact represent additional possible routes of exposure. As a result, in the general population, a very high proportion of individuals exhibit measurable concentrations of BPA in their urine and other biological fluids, including serum, breast milk, amniotic fluid, and semen. Owing to its ubiquitous presence, widespread distribution, environmental persistence, and continuous human exposure, BPA continues to generate worldwide concerns about its possible relationship with a wide spectrum of diseases, including reproductive disorders. This compound is a well-recognized endocrine disruptor with mainly estrogenic activities and, in rodents, the exposure to BPA suppresses serum gonadotrophins and testosterone levels, thus affecting spermatogenesis. Accordingly, a cross-sectional association between higher urinary BPA levels and poorer semen quality has been also reported. Noteworthy, BPA seems to extend its biological toxicity for reproductive health beyond the disruptive effect on the endogenous hormone balance, as, in different species, including human, the in vitro exposure of spermatozoa to BPA induces pro-oxidative and apoptotic mitochondrial dysfunctions, resulting in the loss of sperm motility, viability and DNA integrity. Nevertheless, the few studies that have investigated BPA exposure in relation to male reproduction in humans produced not unequivocal results. On the basis of available evidence, the European Food Safety Authority (EFSA) recently stated that although BPA poses no health risk to consumers because current exposure to the chemical is too low to cause harm, possible effects of BPA on the reproductive system could not be excluded and further evidence is warranted.

In this scenario, public concern about potentially harmful health effects of BPA has led to its removal from many plastic products, particularly related to babies and infants. In its place, structurally similar compounds are being employed, such as bisphenol B (BPB), bisphenol F (BPF) and bisphenol S (BPS). The BPA substitutes-based products are marketed under the label of “BPA-free”, giving the impression of safety, which, however, has not yet been fully verified. Indeed, due to structural similarities with BPA, also these alternatives could exert endocrine disruption activities and some studies on their possible adverse effects on health outcomes, including reproduction, are being reported. In particular, in rodents, the neuroendocrine disruptive effects of BPA analogues lead to behavioral changes and affect testosterone levels, spermatogenesis and sperm DNA integrity.

The objective of this Research Topic is group a collection of original articles, meta-analyses, reviews, or mini-reviews focused on new and more recent insights about the impact of bisphenols on male reproductive health, involving experts from different areas of medicine (endocrinology, andrology, genetic, etc.). We suggest the submission of abstracts with the following proposals: pathophysiology of the possible reproductive toxicity of BPA and its analogues in in vitro and in vivo models, possible reproductive reflections of epigenetic effects of bisphenols, critical reviews on facts and myths regarding the still controversial impact of bisphenols on human reproduction.

We suggest the submission of manuscripts with the following themes (but not limited to):
-pathophysiology of the reproductive toxicity of BPA and its analogues in in vitro and in vivo models
-possible reproductive reflections of epigenetic effects of bisphenols
-prevention and protection strategies.