Proteomic pathway in seminal plasma of men with spinal cord injury (SCI) before and after oral administration of probenecid

Oral probenecid improves sperm motility in men with spinal cord injury

STUDY DESIGN

Prospective cohort study (twenty men with spinal cord injury [SCI]).

OBJECTIVE

Determine if administration of oral probenecid results in improved sperm motility in men with SCI.

SETTING

Major university medical center.

METHODS

Twenty men with SCI were administered probenecid for 4 weeks (250 mg twice a day for 1 week, followed by 500 mg twice a day for 3 weeks). Semen quality was assessed at three time points: pre-treatment, post-treatment (immediately after the 4-week treatment), and follow-up (4 weeks after the last pill was ingested).

RESULT(S)

Probenecid was well-tolerated by all subjects. Sperm motility improved in each subject after 4 weeks of oral probenecid. The mean percent of sperm with progressive motility increased from 19% to 26% (P < 0.05). A more striking increase was seen in the mean percent of sperm with rapid linear motility, from 5% to 17%, (P <0.001). This improvement continued into the four week follow up period. Similar improvements were seen in the total motile sperm count (15 million, 28 million, and 27 million at pre-treatment, post-treatment, and follow-up, respectively). Sperm concentration was not significantly different at pre-treatment, post-treatment, and follow-up, (52 million, 53 million and 53 million, respectively).

CONCLUSION

This study showed that administration of an oral agent (probenecid) known to interfere with the pannexin-1 cellular membrane channel, can improve sperm motility in men with spinal cord injury. It is the first study to report improved sperm motility after oral medication in men with SCI.

Understanding the seminal plasma proteome and its role in male fertility

Seminal plasma is a complex fluid comprised of secretions from the seminal vesicles, the prostate, bulbourethral glands and from the seminiferous tubule lumen / epididymides / vasa deferentia. While it has been established that seminal plasma serves not only as a medium to carry, protect, and nourish sperm after ejaculation up to fertilization, but also as a functional modulator of sperm function, there is still a need to properly characterize the molecular make-up of seminal plasma in fertile men, and to understand how this is altered in different causes of male infertility. The main purpose of this manuscript was to review articles that studied the human seminal plasma proteome, ranging from characterizing a fertile seminal plasma proteomic map to studies comparing seminal plasma from fertile and infertile men, and comparing seminal plasma of fertile or normozoospermic men to a diverse range of biological causes for male infertility. Finally, this review has focused on the association between semen and sperm functional quality and the seminal plasma proteome, in order to demonstrate cellular and molecular mechanisms of male infertility. Due to the untargeted nature of the majority of the studies presented in this review, and to the diverse range of techniques utilized to study the seminal plasma proteomic composition, many differentially expressed proteins were observed. However, in general, it seems that there is a seminal plasma proteome associated to male fertility, and that different biological conditions or cellular phenotypes shift its pathways away from its homeostatic condition to altered energy production pathways. Moreover, it seems there is an inflammatory component to the seminal plasma of infertile men. In conclusion, there are a number of studies focused on the proteomic composition of human seminal plasma; downstream confirmatory studies will help to understand specific pathways of infertility in different biological conditions.