To the Editor:
We would like to thank Dr. Cohen-Bacrie et al for their fine article (1). In this study, they found that sperm DNA damage was correlated with patient age and some sperm parameters, such as total motile sperm count, rapid progression, vitality, and percentage of atypical forms, abnormal necks and coiled tails. However, there was no correlation between sperm DNA damage and number of motile and atypical spermatozoa per ejaculate, progressive motility after 1 hour and amplitude of lateral head displacement, number of spermatozoa with abnormal basal piece or circular flagella, semen volume and sperm concentration, semen pH, morphology of head, acrosome, and intermediate piece, variation of sperm agglutination factors, presence of leukocytes and polynuclear cells in the ejaculated sperm.
Intact human sperm DNA is an essential prerequisite for successful fertilization, and embryo development and abnormal DNA can lead to derangements in the reproductive process. Damaged sperm chromatin or DNA structure is thought to arise due to environmental stresses, gene mutations or chromosomal abnormalities (2). Sperm DNA damage may occur during defective chromatin condensation at spermiogenesis (3). Abortive apoptosis could induce DNA damage (4), and it could also be the result of oxidative stress by reactive oxygen species produced internally or externally (5). Studies have shown a significant positive correlation between sperm DNA fragmentation and levels of reactive oxygen species in testicular tissue (6) and in semen (7).
We think it would be better if the demographics, semen characteristics of the infertile men, and inclusion and the exclusion criteria of the study group were defined. Many factors such as advanced age, environmental stresses, chronic diseases, medications, cancer, abnormal genital examinations (such as varicocele), testicular atrophy and dysplasia may affect sperm DNA structure. The inclusion and exclusion criteria of azoopermic infertiles or infertile men with normal sperm parameters, the number of semen samples with leukocytospermia or the number of patients having different morphologic anomalies like head or tail anomalies may change the results of the correlation analysis between sperm DNA fragmentation and sperm parameters. You may find different statistical results in a more homogenous or well-defined group. The study would benefit from the addition of a multiple regression analysis to determine the independent variables that were associated with sperm DNA fragmentation.
Fatma Ferda Verit, MD Department of Obstetrics and Gynecology Ayhan Verit, MD Department of Urology Harran University, Faculty of Medicine Sanliurfa, Turkey
1. Cohen-Bacrie P, Belloc S, Ménézo YJ, Clement P, Hamidi J, Benkhalifa M. Correlation between DNA damage and sperm parameters: a prospective study of 1,633 patients. Fertil Steril. 2008 Apr 24. [Epub ahead of print]
2. Agarwal A, Said TM. Role of sperm chromatin abnormalities and DNA damage in male infertility. Hum Reprod 2003;9:331–45.3. McPherson SM, Longo FJ. Nicking of rat spermatid and spermatozoa DNA: possible involvement of DNA topoisomerase II. Dev Biol 1993;158:122–30.
3. McPherson SM, Longo FJ. Nicking of rat spermatid and spermatozoa DNA: possible involvement of DNA topoisomerase II. Dev Biol 1993;158:122–30.
4. Sakkas D, Mariethoz E, Manicardi G, Bizzarro D, Bianchi PG, Bianchi U. Origin of DNA damage in ejaculated spermatozoa. Rev Reprod 1999;4:31–7.
5. Aitken RJ, Krausz C. Oxidative stress, DNA damage and the Y chromosome. Reproduction 2001; 122:497-506.
6. Rajesh KT, Doreswamy K, Shrilatha B, Muralidhara M. Oxidative stress associated DNA damage in testis of mice: induction of abnormal sperms and effects on fertility. Mutat Res 2002;513:103–111.
7. Saleh RA, Agarwal A, Nada EA, El-Tonsy MH, Sharma RK, Meyer A, et al. Negative effects of increased sperm DNA damage in relation to seminal oxidative stress in men with idiopathic and male factor infertility. Fertil Steril 2003;79:1597-1605.
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2008.12.102
The Authors Reply
First of all, we thanks Verit and Verit for the interest in our paper.
We are afraid that the authors did not really catch the aim of our paper. We are the reference laboratory of a big ART unit comprising two clinics and more than 40 gynecologists. By law, it is mandatory to have a full spermogram with full morphology (we used WHO rather than Kruger strict criteria) before any type of ART, including artificial insemination. A sperm culture is mandatory as well; in case of infection the ART is postponed, avoiding any artifact linked to infection and massive presence of blood cells (leukocytospermia). DNA fragmentation (DFI) and tertiary structure (i.e., decondensation of DNA) are not requested. However, we complete the exams with these 2 tests:
1. After two failures of fertilization, even when ICSI is performed, as we observed that DNA decondensation may be important in this case.
2. After early embryo developmental arrests when transfer at the blastocyst stage has been proposed.
3. When the paternal age is over 40 (1,2), and when necrospermia is very high.
4. At the special request of the patients or the gynecologists.
Our group is fully aware that DNA quality is of major importance and that injection of highly degraded sperm may severely affect the outcome (3). This aspect has been permanently a source of warning from the group of John Aitken.
The idea was to determine from the completed samples where we have all the information if we can retrieve from the WHO sperm analysis some “flashing lights,” a trend that could drive us, on a regular basis, to determine if we need to immediately include DFI and decondensation in the pre-ART tests. This would help the patients avoid loss of time and ART failures in complicated cases where it is not necessarily immediately accessible.
Dr Paul Cohen Bacrie, Dr Pharm Pr Yves Menezo, PhD, Dr Sci Laboratoire d’Eylau Paris, France
1. Guérin P, Matillon C, Bleau G, Lévy R, Ménézo Y.Impact of sperm DNA fragmentation on ART outcome Gynecol Obstet Fertil. 2005;33: 665-8.
2. Belloc S, Cohen-Bacrie P, Benkhalifa M, Cohen-Bacrie M, De Mouzon J, Hazout A, Ménézo Y. Effect of maternal and paternal age on pregnancy and miscarriage rates after intrauterine insemination. Reprod Biomed Online. 2008;17: 392-7.
3. Fernández-Gonzalez R, Moreira PN, Pérez-Crespo M, Sánchez-Martín M, Ramirez MA, Pericuesta E, Bilbao A, Bermejo-Alvarez P, de Dios Hourcade J, de Fonseca FR, Gutiérrez-Adán A.Long-term effects of mouse intracytoplasmic sperm injection with DNA-fragmented sperm on health and behavior of adult offspring. Biol Reprod. 2008 ; 78:761-72.
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2008.12.103