More good than harm should be expected when Testi-ICSI is applied to oligozoospermic men with post-testicular sperm DNA fragmentation
Editorial

More good than harm should be expected when Testi-ICSI is applied to oligozoospermic men with post-testicular sperm DNA fragmentation

Sandro C. Esteves1, Ahmad Majzoub2, Ashok Agarwal3

1ANDROFERT, Andrology and Human Reproduction Clinic, Referral Center for Male Reproduction, Campinas, SP, Brazil; 2Department of Urology, Hamad Medical Corporation, Doha, Qatar; 3American Center for Reproductive Medicine, Cleveland Clinic, Cleveland, OH, USA

Correspondence to: Prof. Sandro C. Esteves, Director. ANDROFERT, Andrology and Human Reproduction Clinic, Referral Center for Male Reproduction, Campinas, SP, Brazil; Division of Urology, UNICAMP, Av. Dr. Heitor Penteado 1464, Campinas, SP, 13075-460, Brazil. Email: s.esteves@androfert.com.br.

Response to: Turek PJ. Finding the fit: sperm DNA integrity testing for male infertility. Transl Androl Urol 2017;6:S379-80.


Submitted Feb 09, 2017. Accepted for publication Feb 09, 2017.

doi: 10.21037/tau.2017.03.22


We read with interest the commentary by Dr. Paul Turek (1) contextualizing the use of sperm DNA fragmentation (SDF) testing for male infertility in response to the recently published practice recommendations for SDF testing based on clinical scenarios by Agarwal et al. (2).

We certainly concur with the author regarding the limitations of conventional semen analysis parameters as surrogate measures of male fertility potential (3,4) and that SDF testing is one of the most relevant advancements to the andrological evaluation of male infertility (5,6).

Moreover, Dr. Turek critically analyzed the use of testicular in preference over ejaculated sperm for intracytoplasmic sperm injection (ICSI), which has been presented by Agarwal et al. as an alternative to overcome infertility in men with elevated levels of SDF undergoing ICSI (2). In his commentary, the author caution against the indiscriminate use of testicular sperm for ICSI (Testi-ICSI) and rationalize his arguments based on the following premises: (I) there is no indication of Testi-ICSI in cases of failed IVF/ICSI cycles with ejaculated sperm normal or untested SDF; (II) the use of Testi-ICSI in cases of severe oligozoospermia without evidence of sperm DNA damage lacks supportive evidence; and (III) testicular sperm has higher chromosomal aneuploidy rates than ejaculated sperm.

Along these lines, we wish to add some comments that may help readers better understand the matter concerned. Foremost among all is perhaps the fact that the available evidence favoring the use of Testi-ICSI seems to be limited to men with elevated SDF rates in the neat ejaculate. In this scenario, others and we have shown that the rates of SDF are markedly lower in testicular sperm than ejaculated sperm (7-9). We have studied oligozoospermic (5–15 million spermatozoa/mL) men presenting with persistent high SDF (>30%) despite continuous use of oral antioxidant therapy for 3 months and found that SDF rates were fivefold lower in the testis (8.3%±5.3%) than in the semen (40.7%±9.9%; P<0.001) (7). In our study, SDF was assessed using the sperm chromatin dispersion (SCD) method combining a dual fluorescent probe to target both the DNA and proteins that allow discrimination between spermatozoa and other cell elements in testicular suspensions (10).

The biological plausibility of reduced SDF in the testis relies on three essential aspects. First, chromatin compaction is still ongoing during epididymal transit. Second, excessive reactive oxygen species (ROS) can be generated in the epithelial cells of epididymis under physicochemical stressors such as high temperature and environmental conditions (11-13). Lastly, certain endonucleases can cleave DNA of mature live sperm (14). As a result, sperm DNA damage may ensue through different pathways, including hydroxyl radical, nitric oxide, and activation of sperm caspases and endonucleases, thus explaining the positivity for SDF in live ejaculated sperm of infertile men (15). This oxidative-induced damage to the sperm chromatin can be potentially avoided in ICSI candidates provided the epididymis is bypassed.

Notwithstanding, the use of testicular sperm not always overcomes the problem of SDF. Notably, SDF may also occur in the seminiferous tubules as a result of apoptosis or due to defects in chromatin remodeling during spermiogenesis (16). Intratesticular apoptosis induced by impairment in sperm maturation lead to early DNA damage; these spermatozoa traverse the genital tract without being further damaged by oxidative stress (16). Consequently, the advantage of testicular sperm over ejaculated sperm as regards decreasing SDF is likely to be restricted to post-testicular SDF. As suggested by Dr. Turek, and discussed below, it is important to evaluate the male partner of an infertile couple before embarking on assisted reproductive technology (ART). In this context, a comprehensive male infertility evaluation including SDF testing allows not only diagnosing and eventually treating the underlying condition associated with SDF but also identifying the best candidates for Testi-ICSI.

For instance, infertile men with varicocele usually have higher SDF than counterparts without varicocele (12). In these men, reactive oxygen and nitrogen species are released not only in endothelial cells of the dilated pampiniform plexus and testicular cells (developing germ cells, Leydig cells, macrophages and peritubular cells) but also in the principal cells of the epididymis (17). The epididymis can be the origin of SDF in other conditions as well, including infectious and inflammatory states that may contribute to chronic epididymal dysfunctions and spermatogenesis defects associated with residual cytoplasm and defective protamination. The former can be observed in spinal cord injury (18), post-vasectomy reversal (19), and clinical or subclinical epididymitis (20). In these cases, SDF may result from excessive ROS production by spermatozoa themselves in response to a more prolonged epididymal transit or infiltrating polymorphonuclear leukocytes, or both. The latter can be genetically determined or idiopathic, and SDF results from the higher susceptibility of DNA to post-testicular degradation by endonucleases (21). Also, oxidatively-induced SDF can also occur post-ejaculation for a strong association exists between the presence of male accessory gland infections and seminal ROS levels, and between smoking and excessive seminal plasma leukocytes and ROS; both conditions have been associated with high SDF (22,23).

In the study mentioned above involving 147 oligozoospermic patients with elevated SDF, we have shown that the number needed to treat (NNT) by testicular compared to ejaculated sperm to obtain an additional live birth per fresh transfer cycles was 4.9 (95% CI, 2.8–16.8) (7). In other words, we could potentially avoid one out of five oocyte retrievals in such couples. Although this simplistic estimation does not consider the additional contribution of frozen embryos in terms of cumulative live birth rates, the fertilization of an oocyte by a genomically intact testicular spermatozoon may improve the chances of creating a normal embryonic genome that will ultimately decrease the likelihood of miscarriage, which has been more often reported in ICSI cycles with high levels of SDF (24).

Despite the higher aneuploidy rates in testicular sperm compared with ejaculated sperm, as indicated by Dr. Turek, this proportion is still relatively small [approximately 12% in testicular sperm versus 6% in ejaculated counterparts (25)] and are yet to be confirmed in large series of men with oligozoospermia. Notwithstanding, it might be argued that ICSI candidates represent a particular category of patients that would be unlikely to attain natural reproduction. Therefore, a small increase in the risk of having health issues in the offspring could be acceptable in return of a confirmed beneficial effect of Testi-ICSI, provided the actual number of affected individuals were extremely low.

Lastly, although sperm retrievals are invasive interventions, the reported complication rates are very low and often minor (26). The most problematic adverse effect is reduction in testosterone production, which has been reported after large biopsies or repeated procedures in some men with nonobstructive azoospermia (27). On the contrary, from a holistic standpoint, we argue that less invasive treatments for the men (i.e., ICSI with ejaculated sperm) might represent more invasive treatments for the female (i.e., repeat oocyte retrievals) if fewer pregnancies and more miscarriages are obtained with ejaculated sperm in cases of high SDF.

To sum up, we believe there is a rationale for the use of testicular sperm for ICSI in men with high SDF due to the improvement in live birth rates. But at present, the method should be reserved for oligozoospermic men with post-testicular sperm DNA damage who have failed less invasive treatments for known and unknown causes of sperm DNA damage.


Acknowledgements

None.


Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.


References

  1. Turek PJ. Finding the fit: sperm DNA integrity testing for male infertility. Transl Androl Urol 2017;6:S379-80.
  2. Agarwal A, Majzoub A, Esteves SC, et al. Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios. Transl Androl Urol 2016;5:935-50. [Crossref] [PubMed]
  3. Esteves SC. Clinical relevance of routine semen analysis and controversies surrounding the 2010 World Health Organization criteria for semen examination. Int Braz J Urol 2014;40:443-53. [Crossref] [PubMed]
  4. Esteves SC, Hamada A, Kondray V, et al. What every gynecologist should know about male infertility: an update. Arch Gynecol Obstet 2012;286:217-29. [Crossref] [PubMed]
  5. Agarwal A, Cho CL, Esteves SC. Should we evaluate and treat sperm DNA fragmentation? Curr Opin Obstet Gynecol 2016;28:164-71. [Crossref] [PubMed]
  6. Esteves SC, Sharma RK, Gosálvez J, et al. A translational medicine appraisal of specialized andrology testing in unexplained male infertility. Int Urol Nephrol 2014;46:1037-52. [Crossref] [PubMed]
  7. Esteves SC, Sánchez-Martín F, Sánchez-Martín P, et al. Comparison of reproductive outcome in oligozoospermic men with high sperm DNA fragmentation undergoing intracytoplasmic sperm injection with ejaculated and testicular sperm. Fertil Steril 2015;104:1398-405. [Crossref] [PubMed]
  8. Greco E, Scarselli F, Iacobelli M, et al. Efficient treatment of infertility due to sperm DNA damage by ICSI with testicular spermatozoa. Hum Reprod 2005;20:226-30. [Crossref] [PubMed]
  9. Moskovtsev SI, Jarvi K, Mullen JB, et al. Testicular spermatozoa have statistically significantly lower DNA damage compared with ejaculated spermatozoa in patients with unsuccessful oral antioxidant treatment. Fertil Steril 2010;93:1142-6. [Crossref] [PubMed]
  10. Nuñez R, López-Fernández C, Arroyo F, et al. Characterization of sperm DNA damage in Kartagener's syndrome with recurrent fertilization failure: case revisited. Sex Reprod Healthc 2010;1:73-5. [Crossref] [PubMed]
  11. Hamada A, Esteves SC, Agarwal A. Insight into oxidative stress in varicocele-associated male infertility: part 2. Nat Rev Urol 2013;10:26-37. [Crossref] [PubMed]
  12. Cho CL, Esteves SC, Agarwal A. Novel insights into the pathophysiology of varicocele and its association with reactive oxygen species and sperm DNA fragmentation. Asian J Androl 2016;18:186-93. [Crossref] [PubMed]
  13. Rubes J, Selevan SG, Sram RJ, et al. GSTM1 genotype influences the susceptibility of men to sperm DNA damage associated with exposure to air pollution. Mutat Res 2007;625:20-8. [Crossref] [PubMed]
  14. Sotolongo B, Huang TT, Isenberger E, et al. An endogenous nuclease in hamster, mouse, and human spermatozoa cleaves DNA into loop-sized fragments. J Androl 2005;26:272-80. [Crossref] [PubMed]
  15. Muratori M, Tamburrino L, Marchiani S, et al. Investigation on the origin of sperm DNA fragmentation: role of apoptosis, immaturity and oxidative stress. Mol Med 2015;21:109-22. [Crossref] [PubMed]
  16. Gosálvez J, Lopez-Fernandez C, Fernandez JL, et al. Unpacking the mysteries of sperm DNA fragmentation: ten frequently asked questions. J Reprod Biotechnol Fertil 2015;4:1-16. [Crossref]
  17. Agarwal A, Hamada A, Esteves SC. Insight into oxidative stress in varicocele-associated male infertility: part 1. Nat Rev Urol 2012;9:678-90. [Crossref] [PubMed]
  18. Brackett NL, Ibrahim E, Grotas JA, et al. Higher sperm DNA damage in semen from men with spinal cord injuries compared with controls. J Androl 2008;29:93-9; discussion 100-1. [Crossref] [PubMed]
  19. Smit M, Wissenburg OG, Romijn JC, et al. Increased sperm DNA fragmentation in patients with vasectomy reversal has no prognostic value for pregnancy rate. J Urol 2010;183:662-5. [Crossref] [PubMed]
  20. Ollero M, Gil-Guzman E, Lopez MC, et al. Characterization of subsets of human spermatozoa at different stages of maturation: implications in the diagnosis and treatment of male infertility. Hum Reprod 2001;16:1912-21. [Crossref] [PubMed]
  21. Gil-Guzman E, Ollero M, Lopez MC, et al. Differential production of reactive oxygen species by subsets of human spermatozoa at different stages of maturation. Hum Reprod 2001;16:1922-30. [Crossref] [PubMed]
  22. Taha EA, Ez-Aldin AM, Sayed SK, et al. Effect of smoking on sperm vitality, DNA integrity, seminal oxidative stress, zinc in fertile men. Urology 2012;80:822-5. [Crossref] [PubMed]
  23. Ochsendorf FR. Infections in the male genital tract and reactive oxygen species. Hum Reprod Update 1999;5:399-420. [Crossref] [PubMed]
  24. Zhao J, Zhang Q, Wang Y, et al. Whether sperm deoxyribonucleic acid fragmentation has an effect on pregnancy and miscarriage after in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis. Fertil Steril 2014;102:998-1005.e8. [Crossref] [PubMed]
  25. Moskovtsev SI, Alladin N, Lo KC, et al. A comparison of ejaculated and testicular spermatozoa aneuploidy rates in patients with high sperm DNA damage. Syst Biol Reprod Med 2012;58:142-8. [Crossref] [PubMed]
  26. Esteves SC, Miyaoka R, Orosz JE, et al. An update on sperm retrieval techniques for azoospermic males. Clinics (Sao Paulo) 2013;68 Suppl 1:99-110. [Crossref] [PubMed]
  27. Esteves SC. Clinical management of infertile men with nonobstructive azoospermia. Asian J Androl 2015;17:459-70. [PubMed]
Cite this article as: Esteves SC, Majzoub A, Agarwal A. More good than harm should be expected when Testi-ICSI is applied to oligozoospermic men with post-testicular sperm DNA fragmentation. Transl Androl Urol 2017;6(Suppl 4):S381-S384. doi: 10.21037/tau.2017.03.22