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Insight into oxidative stress in varicocele-associated male infertility: part 2

Nature Reviews Urology volume 10, pages 26–37 (2013)Cite this article

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Abstract

Varicocele, the leading cause of male infertility, can impair spermatogenesis through several pathophysiological mechanisms. Of these, current evidence suggests that oxidative stress is the central element contributing to infertility in men with varicocele, to which the testis responds by way of heat stress, ischaemia or production of vasodilators, such as nitric oxide. Surgical varicocele repair (varicocelectomy) is beneficial not only for alleviating oxidative stress-associated infertility, but also for preventing and protecting against the progressive character of varicocele and its consequent upregulations of systemic oxidative stress. However, antioxidant therapy in infertile men with surgically treated and those with untreated varicocele is poorly studied, and well-designed trials are needed.

Key Points

  • Both infertile men with and those without varicocele have elevated levels of reproductive tract ROS; however, such levels are higher in the former, indicating that varicocele exacerbates ROS generation and, consequently, oxidative damage to sperm

  • Varicocele grade is correlated with the severity of oxidative stress—the higher the grade of varicocele, the more severe the degree of oxidative stress

  • Surgical repair is a cost-effective treatment for infertile men with varicocele; such intervention is associated with improvements in various biomarkers of male infertility, such as semen parameters and pregnancy rate

  • By contrast, antioxidant treatments for varicocele-related infertility are poorly studied, and well-designed trials are needed

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Acknowledgements

The authors are supported in part by research funds from the Center for Reproductive Medicine, Department of Urology, Cleveland Clinic, OH, USA.

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Authors and Affiliations

  1. Center for Reproductive Medicine, Glickman Urological and Kidney Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, 44195, OH, USA

    Alaa Hamada & Ashok Agarwal

  2. Androfert, Referral Center for Male Reproduction, Campinas, 13075-460, SP, Brazil

    Sandro C. Esteves

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  1. Alaa Hamada
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A. Hamada researched the data for the article and wrote the manuscript. All authors contributed to the discussion of the article content and edited the manuscript before submission.

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Correspondence to Ashok Agarwal.

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Supplementary information

Supplementary Table 1

Evidence of excessive oxidative stress in men with varicocele (DOC 198 kb)

Supplementary Table 2

Evidence for decreased seminal antioxidant levels in infertile men with varicocele (DOC 120 kb)

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Hamada, A., Esteves, S. & Agarwal, A. Insight into oxidative stress in varicocele-associated male infertility: part 2. Nat Rev Urol 10, 26–37 (2013). https://doi.org/10.1038/nrurol.2012.198

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