Sperm DNA fragmentation in clinical practice

tau.amegroups.com © Translational Andrology and Urology. All rights reserved. We value the comments written by Dr. Benagiano on the “Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios” (1). The author has pointed out the controversies surrounding the diagnostic potential of conventional semen parameters and tests of sperm DNA fragmentation (SDF) in cases of recurrent pregnancy loss and in predicting the outcomes of assisted reproductive techniques (ART). He concluded that SDF testing is a useful tool to assess chromatin integrity and understand the origins and mechanisms of DNA damage, however, its clinical utility is somehow hindered by the lack of well-designed studies and therefore is not widely accepted. Conventional semen analysis is the cornerstone of male fertility evaluation. While it provides useful information on the patency of sperm production, secretions of the accessory organs, as well as ejaculation and emission, it does not predict fertility (2,3). It provides no insights into the functional potential of the spermatozoon to fertilize an ovum or to undergo the subsequent maturation processes required to achieve fertilization. Dr. Benagiano has cited previous studies which showed an association between poor sperm quality and pregnancy outcome (4-7). However, more recent studies have underscored the low diagnostic potential of poor sperm quality in predicting pregnancy outcome whether naturally or through ART. In a retrospective review of 67 patients with severe teratozoospermia (<1% normal forms), Kovac et al. reported natural conception in half the study patients. Moreover, 29% of men with 0% normal forms were still able to conceive (8). Likewise, previous studies reporting a significant influence of sperm morphology on the pregnancy outcome following ART (9) were questioned as some recent studies failed to replicate such an association (10,11). Studies on other semen parameters have yielded similar results too. Lemmens et al . (12) assessed the predictive value of sperm morphology, total progressively motile sperm count, and number of inseminated progressively motile spermatozoa in 4,251 intrauterine insemination cycles. After multivariate analysis, the authors observed that the studied parameters had a low predictive power for pregnancy. The existing drawbacks in the predictive potential of conventional semen analysis triggered the search for other tests that can be utilized in clinical practice (13). SDF testing is a good example of an an ancillary test that can aid clinicians in their efforts to improve patients’ reproductive outcome. In contrast with conventional semen parameters, measures of SDF had better correlation with early embryo development and pregnancy outcomes both naturally and after ART (14,15). Dr. Benagiano has pointed out earlier studies which detected a relationship between sperm quality and early embryo development suggesting that the sperm may have functions that extend beyond being a DNA delivery vessel. However, it is reasonable to postulate that sperm DNA defects are probably more influential on early embryo development. In fact, several studies have confirmed such an association. Simon et al. (14) evaluated 215 men from infertile couples undergoing ART comparing embryo development between low and high SDF groups. They detected a higher percentage of good quality embryos and a lower percentage of poor quality embryos in the low DNA Editorial