Relationship Between Sperm Head Vacuoles and Sperm DNA Alterations in Infertile Men

Are Sperm Head Vacuoles Associated With Sperm Nuclear Alterations?

In men presenting sperm alterations, the selection of genetically undamaged spermatozoa need to be improved in order to increase the success of assisted reproduction treatments.

The aim of this study is to determine whether the presence of sperm head vacuoles is associated with sperm DNA alterations.

The use of intracytoplasmic sperm injection (ICSI) has greatly improved the treatment of severe male infertility, especially for men with oligo-astheno-teratozoospermia (OAT). This in vitro fertilization procedure allows the direct injection of a single spermatozoon into an oocyte. The sperm used for ICSI is selected under a microscope at a 400x magnification. Several studies have reported that de novo chromosomal abnormalities are increased in children born from ICSI , thereby raising the question of the genetic quality of spermatozoa used for ICSI.

A method called MSOME (high magnification Motile Sperm Organelle Morphology Examination), which allows the detailed morphological evaluation of motile spermatozoa in real time and under high magnification (6600x), was developed in 2001. With this technique, fine morphological abnormalities - mainly vacuoles in the head of spermatozoa - were detected. The use of MSOME for the detection of morphologically normal sperm for ICSI gave rise to a technique called IMSI (Intracytoplasmic Morphologically Selected sperm Injection). Higher pregnancy rates were obtained with IMSI compared to ICSI and sperm head vacuoles were found to negatively affect assisted reproduction success rates and embryo development. The use of IMSI also decreases the risk of sex chromosome aneuploidy in embryos .

Several authors found that the presence of large vacuoles in the sperm head correlates with several nuclear alterations: DNA fragmentation , abnormal chromatin condensation and aneuploidy . However, these studies are controversial and were performed on few spermatozoa. In order to improve the selection of spermatozoa with a normal chromosomal content, it is essential not only to confirm the existence of a relationship between sperm head vacuoles and altered sperm nuclear quality but also to better characterize these alterations.

The main goal of this study is to investigate the correlation between sperm head vacuole areas and sperm aneuploidy rates in men with isolated teratozoospermia or OAT. Vacuole areas will be measured by MSOME and aneuploidy rates by FISH for chromosomes 18, X and Y. Moreover, the correlation between sperm head vacuole areas and other nuclear alterations (DNA fragmentation, abnormal chromatin condensation, telomere abnormalities) will be evaluated. Semen samples from 200 patients recruited over a 2-year period will be collected, stored and analyzed.

This study involves the collection of relevant medical information. The computer website for the patient database is secure and protected by a password. The information will be entered and only be viewed by the investigators. On-site monitoring visits will be conducted throughout the study.

Inclusion Criteria:

• men

• 18 years old or more

• affiliated to social security

• with isolated teratozoospermia or oligo-astheno-teratozoospermia according to the WHO guidelines (2010):

  • sperm concentration < 15 million per ml or sperm number < 39 million per ejaculate
  • progressive motility < 35%
  • morphologically normal forms < 50% according to the modified David's classification (Auger et al., 2001
  • mobile spermatozoa selected by density gradient centrifugation > 1 million, in previous spermograms

• with normal constitutional karyotypes (46, XY)

• signed an informed consent

Exclusion Criteria:

• with abnormal constitutional karyotypes
• with a major alteration of sperm parameters, with mobile spermatozoa selected by density gradient centrifugation < 1 million
• under tutorship or guardianship by court order