**Acknowledgements**

*Innovations in Assisted Reproduction Technology*

tract and sperm activity. Failure in sperm production or low sperm count and motility, poor morphology, disturbance in sperm movement and progressive passage through the cervical mucus, uterus, ampulla of the oviducts, capacitation and acrosome reaction, binding zona peluccida, etc. can result in male infertility.

viable fetus, for intrauterine insemination (IUI), IVF or ICSI.

have longer telomeres compared sperm cells in the raw semen [139].

and thus improve sperm motility [140].

**7. Conclusion**

ment or lifestyle changes.

To overcome male infertility in ART different protocols for sperm processing have been developed. There are still many debates on the exact influence of specific techniques used for sperm processing and their benefit to achieve pregnancy. Selecting a proper technique must be strongly individual according the couple's infertility history and ART treatment plan along with semen quality. Isolating an optimal fraction (higher count with progressive movement, morphologically normal rates) of spermatozoa gives the opportunity for selection and usage of the spermatozoa with a better fertilizability and higher chances to contribute for a

Two of the most explored methods for sperm processing in ART—density gradient centrifugation (DGS) and swim-up (SU)—are investigated in details. Compared to fresh sample, the processed one has lower DNA fragmentation rates [134, 135] and lower concentration of ROS regardless which method was used [136, 137].

As there are studies exploring telomere length in reproductive cells (oocytes and spermatozoa) and their connection to infertility, shorter telomeres in spermatozoa might be assumed as a factor causing idiopathic infertility [138]. Truncated telomeres and altered DNA integrity in sperm could negatively influence fertilization, pronuclei formation, embryo morphology and quality and thus could compromise blastocyst formation and implantation. Spermatozoa obtained by either DGC or SU

Some substances such as pentoxifylline (methylxanthine derivate primarily used in intermittent claudication and other vascular disorders treatment) might enhance the motility and quantity of motile sperm after processing. By using pentoxifylline primarily on samples with poor quality increased sperm viability in infertile men with oligoasthenozoospermia, was observed. Samples obtained by PESA or TESE could also be improved by implementing this xanthine derivative in cultural media

Sperm preparation methods along with technical advantages of MSOME allow the selection of sperm cells, with best predictive values, for ART treatments. There are some limitations related to each method used and that is now an open field to research and establish new noninvasive protocols for sperm selection in the routine practice.

Spermatogenesis is a complexed process of division and formation of male reproductive cells. It is highly sensitive to various internal (hormonal regulation, transmitters, growth factors) and external (nutritive substances, therapeutics, drugs, hormones and their metabolites, different toxic substances or X-radiation, increased temperature) factors [141]. Given that the time frame for formation of every new generation of spermatozoa takes approximately 3 months, it should be considered that unfavorable effects purge would be the consequence to time consuming treat-

Modern day society—environment, lifestyle and diet are suspected to be harmful to different processes in the organism such as spermatogenesis and could negatively affect the quality and quantity of life through human lifespan including the ability to reproduce. Considering that sex formation takes place during early fetal development attention to mother's nocuous habits, lifestyle, and environmental specifics should be advert. Events during pregnancy could also influence male

**10**

The authors wish to thank their IVF unit colleagues at Ob/Gyn Hospital "Dr. Shterev" for most helpful discussions while summarizing this chapter.
