Conventional semen analysis (SA) remains an essential tool in the initial male fertility evaluation and subsequent follow-up. However, it neither provides information about the functional status of spermatozoa nor addresses disorders such as idiopathic or unexplained infertility (UI). Recently, assessment of sperm DNA fragmentation (SDF) has been proposed as an extended sperm test that may help overcome these inherent limitations of basic SA. In this review, we aim to: (I) discuss the pathophysiological aspects of SDF, including natural repair mechanisms, causes, and impact on reproductive outcomes; (II) explain different assessment tools of SDF, and describe potential therapeutic options to manage infertile men with high SDF; and (III) analyse the strengths, weaknesses, opportunities and threats (SWOT) of current research on the topic.
This review was constructed from original studies, systematic reviews and meta-analyses that were published over the years up until August 2021, related to the various aspects of SDF.
Different mechanisms lead to high SDF, including defective chromatin packaging, apoptosis, and seminal oxidative stress. The relevance of sperm DNA integrity to male fertility/infertility has been supported by the frequent observation of high levels of SDF in infertile men, and in association with risk factors for infertility. Additionally, high SDF levels have been inversely correlated with the outcomes of natural pregnancy and assisted reproduction. Terminal deoxynucleotidyl transferase dUTP nick end labelling, sperm chromatin structure assay, sperm chromatin dispersion, and Comet assay are four commonly used assays for measurement of SDF. Addressing lifestyle risks and underlying conditions, antioxidants, hormonal therapy, and advanced sperm selection techniques have all been proposed as potential therapeutic options to lower SDF.
The sum of literature provides evidence of detrimental effects of high SDF on both natural and assisted fertility outcomes. Standardization of the techniques used for assessment of SDF and their incorporation into the work up of infertile couples may have significant implications on the future management of a selected category of infertile men with high SDF.
Translational andrology and urology. 2022 Jul [Epub]
Ala'a Farkouh, Gianmaria Salvio, Shinnosuke Kuroda, Ramadan Saleh, Paraskevi Vogiatzi, Ashok Agarwal
Global Andrology Forum, American Center for Reproductive Medicine, Moreland Hills, Ohio, USA., Division of Endocrinology, Department of Clinical and Molecular Sciences (DISCLIMO), Polytechnic University of Marche, Ancona, Italy., Department of Urology, Cleveland Clinic, Cleveland, Ohio, USA., Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Sohag University, Sohag, Egypt., Andromed Health & Reproduction, Fertility Diagnostics Laboratory, Athens, Greece.