An update on clinical and surgical interventions to reduce sperm DNA fragmentation in infertile men

Background Sperm chromatin integrity is essential for normal embryo development and pregnancy outcome. Sperm DNA fragmentation (SDF) testing constitutes a diagnostic tool to measure the proportion of spermatozoa with damaged chromatin in the ejaculate. SDF is associated with potentially treatable conditions, including varicocele, male accessory gland infections, inadequate lifestyle, and gonadotoxin exposure, thus prompting their treatment as a means of improving sperm DNA quality and the reproductive outcomes. Objective To provide an up-to-date review of the role of clinical and surgical interventions on SDF values in subfertile men. Materials and methods An extensive search of studies examining the relationship between male infertility conditions associated with SDF was performed using PubMed and MEDLINE, with a focus on interventional therapy. The start date for the search was not defined, whereas the end date was March 2019. Randomized and non-randomized controlled trials, observational studies, systematic and narrative reviews, and case series were evaluated. Results Treating the underlying male infertility factor seems a promising way to alleviate SDF and to increase the likelihood of achieving natural and assisted conception, but data remain limited. The best evidence relates to varicocele repair and hormonal therapy with the follicle-stimulating hormone. Antioxidant therapy and lifestyle changes might alleviate oxidative sperm markers and decrease SDF but their effects on pregnancy outcomes are still unclear. Among men with high SDF undergoing assisted reproductive technology, the use of testicular spermatozoa in preference over ejaculated spermatozoa for intracytoplasmic sperm injection (ICSI) has been shown to improve pregnancy rates possibly owing to the better sperm chromatin quality in testicular spermatozoa than in ejaculated spermatozoa. Conclusion Current evidence supports interventional therapy as a means to alleviate sperm DNA damage. Identification of the conditions associated with SDF remains important to enable treatment to potentially improve pregnancy outcomes but given the limited data further research is needed to determine the exact role of specific interventional therapy for subfertile men with impaired sperm chromatin.