Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

EU research suggests that PCBs damage sperm – but finds no dramatic effect on male fertility

13.10.2005


Research by an EU-supported international team of scientists has shown that polychlorinated biphenyls (PCBs)[1] - synthetic organic chemicals found widely in the environment and absorbed in the diet – may damage sperm.



But, lead author Dr Marcello Spanò, of the Italian National Agency for New Technologies, Energy and the Environment (ENEA), stressed that the study had found no dramatic effects on human fertility and had not revealed any serious public health threat. However, the findings were a warning and further research was needed.

The study, reported on line (Thursday 13 October) in Europe’s leading reproductive medicine journal Human Reproduction[2], also looked at dichlorodiphenyldichlorethylene (DDE) – a breakdown product of DDT[3] – but found that it did not appear to damage sperm DNA.


The impact of persistent organochlorine pollutants (POPs)[4], of which PCBs and DDT are two, on human fertility is still unknown and there are limited and contradictory findings so far as to whether PCBs and DDT/DDE damage human sperm. This study, which is part of a wide-ranging project known as INUENDO[5], set out also to see whether these two POPs damage sperm by altering its chromatin integrity. (Chromatin is the DNA and associated proteins that make up a chromosome).

The research, which is the first to collate data about reproductive effects of POPs from a general population, involved over 700 men – 193 Inuits from Greenland, 178 Swedish fishermen, 141 men from Warsaw in Poland and 195 men from Kharkiv in Ukraine.

The scientists used Sperm Chromatin Structure Assay (SCSA)[6] to test the integrity of sperm samples from the majority of the volunteers and assess the level of DNA damage – the DNA fragmentation index (DFI). They measured blood serum for levels of hexachlorobiphenyl (CB-153), which is a marker for total non dioxin-like PCBs in the body. The men also answered questionnaires on their lifestyle, occupations and reproductive history.

The results produced an intriguing and puzzling finding: among the European men overall, the DFI rose in concert with rising levels of PCBs in the blood, with sperm DNA fragmentation reaching a 60% higher average level in the group exposed to the highest levels of POPs. But, no such significant association was found among the Inuit men.

"The results from the Inuit cohort are surprising and reassuring. As usual, we wanted a simple answer and instead we found a lot of new questions," said Dr Spanò, who is Group Leader, Reproductive Toxicology, Section of Toxicology and Biomedical Sciences at ENEA in Rome. "We can only speculate, at this stage, that genetic make-up and/or lifestyle factors seem to neutralise or counterbalance the pollutants in this group."

It could be, he said, that the profile of the pollutants played a role. PCBs are a class of compounds that include around 200 toxic by-products (congeners). "We measured only two important POPs as it would be a Herculean task to consider them all, so we are seeing only the tip of the iceberg."

Dr Spanò said it was important to keep the results in perspective. The median level of damaged sperm DNA was 10% and the large majority of men in the study were fertile. The probability of fathering a child starts to decrease when the proportion of damaged sperm reaches about 20% and becomes negligible from 30-40% onwards. "PCB exposure might negatively impact reproductive capabilities especially for men who, for other reasons, already have a higher fraction of defective sperm," he said.

Research priorities now include time-to-pregnancy studies (already underway) and regional differences. "But what we badly need are data on exposure of unborn babies, as the endocrine disruption hypothesis suggests that foetal and peri-natal exposure could be more relevant as far as health and reproductive consequences are concerned," he said.

He added that there were few epidemiological studies of the reproductive effects of POPs and population studies were imperative for better risk assessment. This research paper was the first of many that would report the overall findings of the project. INUENDO was a major undertaking only made possible by the skill and enthusiasm of the international research teams and the thousands of people who had contributed information and biological samples, said Dr Spanò. "We are indebted to them."

Margaret Willson | EurekAlert!
Further information:
http://www.eshre.com/emc.asp

More articles from Life Sciences:

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

nachricht How protein islands form
15.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>