By Denise Donati
The Sperm Chromatin Structure Assay (SCSA) is a new method developed to evaluate the chromatin within a sperm. The chromatin is the genetic material that is contained within the nuclear part of the head of the sperm. The SCSA is a way of measuring the level of DNA fragmentation in the sperm (the damaged sperm) to enhance the diagnosis of and treatment for male fertility.
Approximately one in every six couples are affected by infertility, causes include factors of the male, female, or both partners. Nearly 30% of couples presenting at an IVF clinic can be attributed to the female, 30% present with male complications, and 30% can be related to both the female and male. For the final 10% of couples, a cause can never be identified.
Sperm Chromatin Testing
In previous years, male fertility was evaluated by a semen analysis only. But new studies have shown that reduced male fertility can be associated with a certain level of damaged sperm chromatin. When presenting at a fertility clinic for the first time, prior to your treatment, it is essential that the male partner produces a semen sample for analysis. The laboratory assess the semen quality by looking at the amount of sperm in the sample (concentration), counting the number of sperm swimming correctly (motility), and having a look to see if the sperm look normal (morphology).
Other parameters are assessed by the scientist and a letter of recommendation for your treatment is posted to your specialist. This is, however, only based on a visual assessment on how likely the sperm are to fertilize the egg, and not an insight into the genetic material of the sperm.
Trials have shown that the fertilization rates of men containing low numbers of sperm chromatin damage are only slightly higher to those who have quite high sperm chromatin damage. It is becoming evident that those men with higher levels of sperm chromatin damage, although fertilizing the eggs, are not resulting in a pregnancy. The embryos created by sperm with increased DNA fragmentation have a decreased capability of implanting and creating an on-going pregnancy. Therefore, the integrity of the chromatin and the amount of chromatin that is damaged is very important.
The Sperm Chromatin Structure Assay that we refer to is the most informative and a very sophisticated assay that uses a fluorescence activated cell sorter. Within approximately a minute, this cell sorter can look at thousands of sperm. The abnormal and normal sperm are stained (green for normal DNA and red for abnormal DNA) and these quantities are measured. The results are compared with known normal sperm. The ratio of normal sperm to the assayed sperm is calculated and this is the most important in determining the quality of the sperm.
A small amount of chromatic damage occurs in most men and is considered to be normal. Very limited information has been released and it is not greatly known what the causes are to create damage to sperm chromatin and if it is indeed reversible.
It has been thought that infections, increased toxins and temperature may play a role in the mechanisms for causing sperm chromatin damage. Long periods of abstinence (ejaculation) and a patient’s age may also cause greater DNA fragmentation to the sperm. It has also been put forward that frequent ejaculations, avoiding smoking, and decreasing the toxic chemicals that may harm sperm production may be worth following.
The SCSA is not for everyone and should not replace the semen analysis as an initial tool for male infertility, as both tests examine different aspects of the sperm. The SCSA may assist couples that have had any of these issues:
- Unexplained infertility
- Multiple IVF treatments without achieving fertilization
- Embryos transferred, but no pregnancies have resulted
Some studies also suggest an increase in miscarriages whose causes are unidentified may also be related to increased sperm DNA damage.
If you feel you might fit the criteria in which a Sperm Chromatin Structure Assay might be beneficial, please do not hesitate to contact Fertility Solutions Sunshine Coast and Bundaberg and speak to one of our scientists at 1300 337 845 (1300 FERTILITY).