Posts Tagged ‘ICSI’

“Klingon Cloaking Device” May Be Key to Male Infertility

The lack of a protein that normally coats sperm may be the reason why some sperm don’t reach the egg to fertilize it.

This protein acts as a “Klingon cloaking device” to allow sperm to swim through cervical mucus and avoid the immune system on its long journey to the egg, says Gary Cherr, a professor at the UC Davis Bodega Marine Laboratory and Center for Health and Environment.

The protein DEFB126 is generated by a specific gene, and men with two copies of the defective gene do not produce the protein, the researchers reported in a study published online on July 20 in the journal Science Translational Medicine.

Some 70% of men have infertility that can’t be explained based on their sperm count and quality, say the researchers.

This discovery may help explain a significant portion of this infertility.

In tests of men worldwide, they found about half of all men carry 1 defective copy.

One quarter have 2 defective copies and therefore make sperm that are poor at swimming through cervical mucus.

In studying about 500 couples in China who were trying to become pregnant, they found that men with 2 copies of the abnormal gene were 30% less likely to father a child over about a 2-year period.

And it took nearly 2 months longer for the couples to have a baby if the man had 2 copies of the abnormal gene.

The researchers are now looking to develop a test for the mutation.

If a couple found that the man has a double mutation, they could go directly to single-sperm injection with intracytoplasmic sperm injection, or ICSI, to inseminate the woman’s egg.

Choosing a healthy sperm becomes crucial to ICSI success.

In a natural conception, only the fittest and healthiest sperm makes the arduous journey to the egg.

ICSI bypasses this natural selection barrier, so the chances of a genetically abnormal sperm fertilizing an egg are higher.

A new test for sperm DNA damage could help select the best sperm for a single-sperm injection.

Cancer Survivors Can Father Children

Men who have a zero sperm count from cancer treatments may still have a chance to father a child.

“We can usually retrieve sperm from the testicles of 30-50% of men who had chemotherapy even 15 or more years ago. Using ICSI, about 20% take home a baby,” write Weill Cornell Drs. Zev Rosenwaks and Marc Goldstein in A Baby at Last!

Sperm can be extracted using a procedure called microdissection testicular sperm extraction (TESE), a procedure that was developed by Weill Cornell researchers.

The procedure enables doctors to identify small areas in the testicles where sperm are made and then carefully extract these healthy sperm cells, even in men whose testicles have been severely damaged by chemotherapy. These sperm are then directly injected into a woman’s egg using an advanced in vitro fertilization (IVF) procedure called ICSI, which stands for intracytoplasmic sperm injection.

In a new study published online in the Journal of Clinical Oncology on March 14, Weill Cornell researchers report on more than 1,000 TESE procedures on nearly 900 men, including 73 cancer patients.

The researchers retrieved sperm in 27 (37%) of the cancer survivors, which led to the birth of 20 children using IVF techniques.

If you have cancer, the type of cancer and type of chemotherapy you receive affects your chances of successful sperm retrieval. For men with testicular cancer who received platinum drugs, the sperm retrieval rate was 85%. Men with lymphoma treated with an alkylating agent such as cyclophosphamide had lower retrieval rates, ranging from 26-36%. Sarcoma patients had the lowest retrieval rate, only 14%.

“When we started this study, we thought sperm retrieval rates would be close to zero among the group of cancer survivors, but we were surprised to discover that in many cases small areas of testicular tissue survived and resumed sperm production over a period of several years,” said lead author Peter Schlegel, MD, chairman of the Department of Urology at Weill Cornell Medical College, in a press release about the study.

“This study gives men a new way to achieve fertility and the potential of parenthood. Survivors of childhood cancer should be made aware of options besides using banked sperm, adoption or donors if they want to be fathers,” noted Lisa Diller, MD, Associate Professor of Pediatrics, Harvard Medical School, in the release.

Because the numbers of sperm retrieved from the testicles of cancer survivors are low, TESE is best performed at the time of egg retrieval so that fresh sperm can be immediately injected into the egg using ICSI. Any extra sperm can be frozen and preserved for future use.