Navigation Links
Normal-looking sperm may have serious damage; scientists urge more care in selection
Date:7/8/2008

This release is available in Spanish.

Barcelona, Spain: Intracytoplasmic sperm injection (ICSI), where a single sperm is injected into an egg to fertilise it, is increasingly used to help infertile men father children. Although the sperm chosen for the procedure may appear quite normal, researchers in the US have found that many of them in fact have DNA damage, which can decrease the chances of pregnancy.

Mr. Conrado Avendao, from the Jones Institute for Reproductive Medicine, Norfolk, Virginia, USA, and colleagues studied a group of infertile men with moderate and severe teratozoospermia, where most of the sperm looks abnormal. He told the 24th annual conference of the European Society of Human Reproduction and Embryology today (Tuesday 8 July) that, in this group of men, the embryologist would normally select the 'best looking' sperm for injection. "This would typically be done by analysing the sperm's shape under a microscope," he said. "A 'good' sperm by this criterion would have a regular oval head and a long straight tail. However, our research has shown that appearances can be deceptive."

Mr. Avendao and colleagues studied sperm from ten infertile men and found that, despite appearing to be completely normal, many of them had DNA damage (DNA fragmentation). "In routine ICSI procedure, the embryologist chooses the best-looking sperm under the microscope, but it could be damaged," he said. "DNA-damaged sperm has a highly deleterious effect on the ability to achieve a pregnancy. Even if damaged sperm are used and the woman becomes pregnant, the chances of miscarrying are significantly higher."

The researchers compared levels of DNA fragmentation in sperm from the infertile group with that from fertile men. The study was performed by a simultaneous examination of normal sperm morphology using face contrast and DNA fragmentation by fluorescence microscopy. The sperm morphology was evaluated in 400 randomly selected cells per sample. When a sperm with normal morphology was found, the light was switched to fluorescence to determine DNA integrity. Sperm with normal morphology from the fertile group showed no evidence of DNA fragmentation. But in the infertile men, between 20 and 66% of normal-looking sperm had DNA damage.

"The origin of DNA fragmentation can be multi factorial," said Mr. Avendao. "Oxidative stress (mainly due to reproductive tract infections) and apoptosis are the most studied, but other factors as age, smoking, exposure to air pollution and abnormal testicular warming are believed to increase the proportion of sperm DNA fragmentation."

The researchers are now applying DNA fragmentation evaluation to couples with male factor infertility. "Our preliminary results using this new evaluation method show a clear negative correlation between the percentage of DNA fragmented sperm and the embryo quality and pregnancy outcome," said Mr. Avendao.

"Different research groups have shown that in addition to affecting normal embryonic development, fertilisation with damaged spermatozoa resulting in a live-born infant can be associated with increased chromosomal abnormalities, minor or major birth defects, and even childhood cancer," said Mr. Avendao. "Our work has shown that normal sperm morphology alone should not be used as the unique attribute for the selection of sperm for ICSI. New methods that allow an accurate separation of sperm with intact DNA should be sought."

Sperm biology has received less attention since the introduction and success of the ICSI technique, say the researchers. "While the ICSI procedure bypasses the natural sperm selection, we believe that the deleterious effects of injecting a DNA-fragmented sperm should and can be avoided. Further research into sperm biology is essential if we are to avoid problems in the future," said Mr. Avendao.


'/>"/>

Contact: Mary Rice
mary@mrcommunication.org
34-932-308-810
European Society for Human Reproduction and Embryology
Source:Eurekalert

Related biology news :

1. Wiggle room: Cornell researcher borrows idea from sperm to provide energy for nanoscale robots
2. Mutant sperm guide clinicians to new diseases
3. Primate sperm competition: speed matters
4. Bacterial slime helps cause serious disease
5. Oceanic sharks worldwide at serious risk from high-seas fishing, rising demand for shark products
6. West Nile virus spread through nerve cells linked to serious complication
7. Study finds blocking angiogenesis signaling from inside cell may lead to serious health problems
8. Biodiversity maps developed by UCSD scientists will help guide conservation measures in East Africa
9. Scientists integrate data in three dimensions to study climate effects on young fish
10. Scientists set out to measure how we perceive naturalness
11. Scientists reveal the key mechanisms for affinity between transient binding proteins
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/13/2017)... India , April 13, 2017 According to ... Proofing, Identity Authentication, Identity Analytics, Identity Administration, and Authorization), Service, Authentication Type, ... MarketsandMarkets™, the IAM Market is expected to grow from USD 14.30 Billion ... Growth Rate (CAGR) of 17.3%. ... MarketsandMarkets ...
(Date:4/11/2017)... April 11, 2017 No two people ... at the New York University Tandon School of ... have found that partial similarities between prints are ... in mobile phones and other electronic devices can ... The vulnerability lies in the fact that fingerprint-based ...
(Date:4/5/2017)...  The Allen Institute for Cell Science today announces ... portal and dynamic digital window into the human cell. ... application of deep learning to create predictive models of ... a growing suite of powerful tools. The Allen Cell ... publicly available resources created and shared by the Allen ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... AMRI, a global contract ... to improve patient outcomes and quality of life, will now be offering its ... attributed to new regulatory requirements for all new drug products, including the finalization ...
(Date:10/11/2017)... Charlotte, N.C. (PRWEB) , ... October 11, 2017 ... ... ARCS® Foundation President Andi Purple announced Dr. Suneel I. Sheikh, the ... Laboratories ( ASTER Labs ), Inc. has been selected for membership in ...
(Date:10/11/2017)... ... ... a basic first aid supply for any work environment, but most personal eye wash can ... a dangerous substance enters both eyes? It’s one less decision, and likely quicker response time ... , “Whether its dirt and debris, or an acid or alkali, getting anything in your ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ... announced today it will be hosting a Webinar titled, “Pathology is going digital. ... Associates , on digital pathology adoption best practices and how Proscia improves lab ...
Breaking Biology Technology: