Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Technique may allow cancer patients to freeze eggs, preserving fertility before starting treatment

31.05.2005


U-M researchers identify method that produces viable eggs when thawed

A new technique might allow women diagnosed with cancer the opportunity to have children when chemotherapy and radiation treatments rob them of their fertility, researchers at the University of Michigan Comprehensive Cancer Center have found. By having her eggs frozen before she begins cancer treatments, a woman can preserve the hope of one day having a baby.

Freezing eggs is one thing; thawing them safely so they can lead to pregnancy is the challenge. In the past, efforts to freeze a woman’s eggs, or oocytes, have not worked well because the cells are large. When the egg is thawed, ice crystals cause damage that prevents the egg from being fertilized.



U-M researchers looked beyond traditional techniques to a method of freezing cells called vitrification. This cryopreservation technique allows the eggs to be cooled fast enough that the transformation from liquid to solid is instantaneous. No ice crystals form and the consistency resembles a viscous glassy state. Research so far has used mouse oocytes but U-M expects to make the technology available in the clinic soon.

"With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, we are getting 98 percent survival. For a woman with cancer, these are the only eggs she’s ever going to have, so it’s important that as many as possible remain viable," says Gary D. Smith, Ph.D., associate professor of obstetrics and gynecology, urology, and molecular and integrative physiology at the U-M Medical School, and director of the Fertility Counseling and Gamete Cryopreservation Program at the U-M Comprehensive Cancer Center.

Smith will present results of his research on Sunday, May 29, at the World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics in Istanbul, Turkey.

Cancer treatments such as chemotherapy and radiation therapy can cause damage to a woman’s reproductive system and leave her unable to have children afterward. Some women may regain their reproductive function after their treatment ends and may be able to conceive on their own, while others will become infertile. Egg cryopreservation could be insurance for those women at highest risk of fertility problems after cancer treatment.

When a woman wishes to become pregnant, the vitrified eggs would be warmed and then fertilized with male sperm. The fertilized eggs would then be transferred to the uterus in the same procedure that’s used successfully when couples freeze embryos.

When eggs are warmed after vitrification, fertilization rates with conventional IVF are low. Instead, researchers have found, a single sperm cell must be injected into a single oocyte, a technique called intracytoplasmic sperm injection, or ICSI. While ICSI is an established technique used in assisted reproduction, it is more complex and costs more than traditional methods.

Using mouse oocytes, 80 percent of eggs that had been vitrified became fertilized with ICSI, with a live birth rate of about 30 percent, comparable to conventional IVF when eggs are not frozen. The fertilization and birth rates for vitrified eggs are similar to the rates for control eggs that were not vitrified.

For egg freezing to work, it must be a mature oocyte, which means a woman must have 14 days of hormone treatments to stimulate mature egg production. This could limit its applications for some women. Researchers question if it is appropriate for women with cancers fueled by estrogen, such as breast cancer. In addition, the hormone treatments require delaying the start of cancer therapy, which may not be an option for every patient.

Guidelines for patients and physicians still need to be established as the technique begins to be offered in a clinic setting, Smith says. "This is a very new technology and it requires education both of patients and physicians," Smith says.

U-M has cryopreserved eggs for one patient; however, the service is currently not offered while researchers seek approval for a clinical trial. A specialized clinic in the U-M Comprehensive Cancer Center provides counseling and information for women considering their fertility options, and the clinic currently freezes embryos for cancer patients who have a partner. The clinic also offers counseling and sperm freezing for male cancer patients. U-M will offer egg vitrification only to women facing cancer treatments, because the long-term safety of this technique remains unknown.

"In a woman with cancer, if she is going to lose her reproductive capacity because of cancer treatments, this is her only choice to have baby with her own eggs," Smith says. A clinical trial through the U-M Comprehensive Cancer Center is planned to begin by fall.

Nicole Fawcett | EurekAlert!
Further information:
http://www.umich.edu
http://www.cancer.med.umich.edu/clinic/fertilityclinic.htm

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>