BERKELEY, CA (UroToday.com) - DNA fragmentation in spermatozoa is an important parameter in the diagnosis and management of male infertility. Debate remains as to whether it should be included as part of the routine semen analysis, but in practice it is likely that cost is the deciding factor. DNA fragmentation indices correlate well with infertility, incidence of spontaneous abortion, and poor IVF outcome. High DNA fragmentation can also exist in normozoospermic men. Therefore this is an important diagnostic tool for couples with ‘unexplained’ infertility and it may also present where infertility is only suspected on the female side.
High DNA fragmentation may result in recurrent failed IVF or recurrent miscarriage, and couples should be counselled to proceed directly to ICSI. Importantly however, whilst ICSI has higher delivery rates, there may be an increased risk of inheritance of damaged DNA by the offspring. Where possible, DNA fragmentation should be addressed and minimised before ART despite the potential for success with ICSI.
Oxidative stress is the major cause of DNA fragmentation in spermatozoa. As outlined in the paper, a number of medical, environmental, and nutritional causes of oxidative stress can be treated with success. Leukocytospermia is a major source of oxidative stress to spermatozoa and any relevant infection should be treated. Varicocele occurs in 40% of infertile males and the gold standard treatment is micro-surgical repair, after which, fertility may be restored in some cases. Environmental or lifestyle patterns that contribute to oxidative stress may be easily modified without risk, even in the absence of definitive evidence. This may include avoidance of smoking, toxic metals, xenobiotics, testicular heat, mobile phone radiation, and a reduction in body mass. In the absence of larger clinical trials, it could be argued that it is premature to advise major lifestyle changes in couples with other causes of infertility. However where high DNA fragmentation has been identified, it may be cautious to avoid the above sources of oxidative stress.
In terms of nutritional changes, nutritional sources of antioxidants may play a significant role. However some pro-oxidative processes are essential to spermatozoan function, such as capacitation, initiation of the acrosome reaction, and ultimately fertilisation. High levels of supplementation may therefore have risks and should only be carried out where deficiency or necessity have been determined by relevant tests, under the supervision of a dietician or nutritional therapist. Food source antioxidants, however, are low risk and the diet should be easily modifiable to include sources of zinc, selenium, and vitamin C and E, at a minimum.
Whilst being conservative based on the balance of oxidation-reduction necessary for spermatozoan function and the fact that definitive evidence is currently lacking, there remains a number of low-risk modifications that may help to reduce oxidative stress in infertile men.
Ciara Wright, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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