Another Sperm Magnet...
Posted on 07/02/2002 5:57:25 AM PDT by Pharmboy
VIENNA (Reuters Health) - US scientists said on Monday they have developed a biological "magnet" for healthy sperm that will allow them to weed out those that are genetically faulty before carrying out assisted reproduction.
Professor Gabor Huszar from Yale University in New Haven, Connecticut, said that intracytoplasmic sperm injection (ICSI)--which is used to overcome male infertility by injecting a single sperm directly into the egg--bypasses the evolutionary sperm selection process.
"We do not know for sure what the risks are of allowing these genetically damaged sperm that would normally never fertilise the egg to cause a pregnancy," he told the European Society for Human Reproduction and Embryology meeting here.
"There have been suggestions that we have been passing on chromosome abnormalities, and that we might be creating various problems for the future. This is all speculation, but what we do know is that using this new sperm selection method we have a chance of eliminating these concerns."
Huszar and his team have developed a method for selecting individual mature sperm with very low frequencies of chromosomal aberrations and a high degree of DNA integrity, which they say should eliminate concern that children born as a result of ICSI could be at risk of chromosome abnormalities.
The researchers had previously found a close correlation between immature sperm and the frequency of aneuploidies--where sperm have abnormal numbers of each chromosome.
The link is based on a sperm protein called HspA2, which is both a molecular "scaffold" for chromosomes during cell division, and involved in the binding sperm to a molecule in the female reproductive tract called hyaluronic acid.
The team found that by using hyaluronic acid as a kind of "mature sperm magnet" they could reduce the number of sperm with chromosomal abnormalities significantly.
Sperm that stuck to hyaluronic acid patches on Petri dishes tended to be mature sperm with fewer chromosome problems.
Huszar and colleagues tested the incidence of chromosomal aberrations in normal semen of 12 men with low sperm counts and 12 with normal sperm levels, as well as the fraction of sperm "selected" by the hyaluronic acid for both groups.
Chromosomal abnormalities were reduced four- to five-fold in the hyaluronic acid-bound sperm fraction from men with normal and diminished sperm concentrations.
From 0.04% to 0.13% of the sperm selected by the hyaluronic acid (HA) had an abnormal number of chromosomes, Huszar said in a statement. This proportion did not change based on the percentage of the original sperm sample that was abnormal, he noted.
"The HA method represents a major breakthrough in ICSI sperm selection, and it is safe and efficient. We are testing the hypothesis that the HA selected sperm is equivalent to those sperm that cause fertilisation in the natural conception process."
Another Sperm Magnet...
Planned Parenthood better start filling the sandbags!
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