Sperm preparedness and adaptation to osmotic and pH stressors relate to functional competence of sperm in Bos taurus

The adaptive ability of sperm in the female reproductive tract micromilieu signifies the successful fertilization process. The study aimed to analyze the preparedness of sperm to the prevailing osmotic and pH stressors in the female reproductive tract. Fresh bovine sperm were incubated in 290 (isosmotic-control), 355 (hyperosmotic-uterus and oviduct), and 420 (hyperosmotic-control) mOsm/kg and each with pH of 6.8 (uterus) and 7.4 (oviduct). During incubation, the changes in sperm functional attributes were studied. Sperm kinematics and head area decreased significantly (p < 0.05) immediately upon exposure to hyperosmotic stress at both pH. Proportion of sperm capacitated (%) in 355 mOsm/kg at 1 and 2 h of incubation were significantly (p < 0.05) higher than those in 290 mOsm media. The magnitude and duration of recovery of sperm progressive motility in 355 mOsm with pH 7.4 was correlated with the ejaculate rejection rate (R2 = 0.7). Using this information, the bulls were divided into good (n = 5) and poor (n = 5) osmo-adapters. The osmo-responsive genes such as NFAT5, HSP90AB1, SLC9C1, ADAM1B and GAPDH were upregulated (p < 0.05) in the sperm of good osmo-adapters. The study suggests that sperm are prepared for the osmotic and pH challenges in the female reproductive tract and the osmoadaptive ability is associated with ejaculate quality in bulls.

The antidepressant Sertraline inhibits CatSper Ca2+ channels in human sperm

STUDY QUESTION Do selective serotonin reuptake inhibitor (SSRI) antidepressants affect the function of human sperm? SUMMARY ANSWER The SSRI antidepressant Sertraline (e.g. Zoloft) inhibits the sperm-specific Ca2+ channel CatSper and affects human sperm function in vitro. WHAT IS KNOWN ALREADY In human sperm, CatSper translates changes of the chemical microenvironment into changes of the intracellular Ca2+ concentration ([Ca2+]i) and swimming behavior. CatSper is promiscuously activated by oviductal ligands, but also by synthetic chemicals that might disturb the fertilization process. It is well known that SSRIs have off-target actions on Ca2+, Na+ and K+ channels in somatic cells. Whether SSRIs affect the activity of CatSper is, however, unknown. STUDY DESIGN, SIZE, DURATION We studied the action of the seven drugs belonging to the most commonly prescribed class of antidepressants, SSRIs, on resting [Ca2+]i and Ca2+ influx via CatSper in human sperm. The SSRI Sertraline was selected for in-depth analysis of its action on steroid-, prostaglandin-, pH- and voltage-activation of human CatSper. Moreover, the action of Sertraline on sperm acrosomal exocytosis and penetration into viscous media was evaluated. PARTICIPANTS/MATERIALS, SETTING, METHODS The activity of CatSper was investigated in sperm of healthy volunteers, using kinetic Ca2+ fluorimetry and patch-clamp recordings. Acrosomal exocytosis was investigated using Pisum sativum agglutinin and image cytometry. Sperm penetration in viscous media was evaluated using the Kremer test. MAIN RESULTS AND THE ROLE OF CHANCE Several SSRIs affected [Ca2+]i and attenuated ligand-induced Ca2+ influx via CatSper. In particular, the SSRI Sertraline almost completely suppressed Ca2+ influx via CatSper. Remarkably, the drug was about four-fold more potent to suppress prostaglandin- versus steroid-induced Ca2+ influx. Sertraline also suppressed alkaline- and voltage-activation of CatSper, indicating that the drug directly inhibits the channel. Finally, Sertraline impaired ligand-induced acrosome reaction and sperm penetration into viscous media. LIMITATIONS, REASONS FOR CAUTION This is an in vitro study. Future studies have to assess the physiological relevance in vivo. WIDER IMPLICATIONS OF THE FINDINGS The off-target action of Sertraline on CatSper in human sperm might impair the fertilization process. In a research setting, Sertraline may be used to selectively inhibit prostaglandin-induced Ca2+ influx. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Swiss Centre for Applied Human Toxicology (SCAHT), the Département de l’Instruction Publique of the State of Geneva, the German Research Foundation (CRU326), the Interdisciplinary Center for Clinical Research, Münster (IZKF; Str/014/21), the Innovation Fund Denmark (grant numbers 14-2013-4) and the EDMaRC research grant from the Kirsten and Freddy Johansen’s Foundation. The authors declare that no conflict of interest could be perceived as prejudicing the impartiality of the research reported. TRIAL REGISTRATION NUMBER NA.

P–185 Overcoming a sudden COVID–19 lockdown and other similar unforeseen adverse events: Oocyte-sperm cryopreservation 4 hours after conventional in vitro insemination

Study question Can human oocytes be cyropreserved when they were previously inseminated while obtaining normal fertilization, embryo development and pregnancies? Summary answer Cryopreservation of recently inseminated human oocytes produces normal 2PN zygotes, viable embryos and ongoing pregnancies. What is known already Oocyte vitrification is a well-established technique in the infertility field supported by its effectiveness to freeze and thaw embryos at various stages of development. However, it is yet unknown whether cryopreservation performed in a period between conventional in vitro insemination and the appearance of pronuclei, affects any of the steps leading to fertilization, thereby arresting this process. Study design, size, duration Case report that includes 5 IVF cycles where cryopreservation and thawing were performed in a pre-zygote stage, 4 hours after the conventional insemination of oocytes. The rationale for this procedure was to comply with a government restriction to circulate and work in order to prevent the spread of the SARS-CoV–2 virus, unexpectedly 3 days ahead (effective on 03/19/2020). Participants/materials, setting, methods: Off-site embryologists cancelled all pending embryo transfers and returned home (2,000 km away) before the stay-home quarantine. Five couples were informed and consent was obtained on the urgent need to cryopreserve their already inseminated oocytes despite of the limited scientific information. We vitrified 28 oocyte-sperm pairs in vitrification devices containing 2 to 3 inseminated oocytes each. Main results and the role of chance Eight months later all non-essential activities, including non-urgent procedures in hospital facilities, were permitted again, allowing embryologists to travel and resume their postponed work. We thawed 19 of the so-called “pre-zygotes” corresponding to 4 of the 5 initial couples. Female ages were 29, 39, 38 and 37 years old. Our primary outcomes were detection of pronuclei and the occurrence of fertilization. The secondary outcome was pregnancy success. On day 1, we observed the presence of 2PN in 16 oocytes (84%). Only one patient with 2 oocytes failed to fertilize. We transferred 2 good-to-fair-grade cleaved embryos to each of the 3 patients, obtaining one pregnancy with a positive fetal heartbeat from the 39 years old patient. Two of the couples were also able to cryopreserve 2 and 1 surplus embryos on day 5, respectively. Limitations, reasons for caution Our strategy was used exclusively to overcome an unexpected adverse event while complying with State and County regulations on COVID–19. As a case report, a large sample size is needed to confirm and extend these results including the putative detrimental effects of arresting the fertilization process through vitrification. Wider implications of the findings: Although cryopreservation implies to arrest of any stage of a development continuum, to the best of our knowledge, this is the first time that both fertilization and pregnancy were achieved after halting the fertilization process long before the appearance of pronuclei (at ∼4 hours after insemination). Trial registration number Not applicable

O-228 The SSRI antidepressant Sertraline inhibits CatSper calcium channels in human sperm

Study question Do Selective Serotonin Reuptake Inhibitor (SSRI) antidepressants affect the function of human sperm? Summary answer The SSRI-antidepressant Sertraline (e.g. Zoloft) inhibits the sperm-specific Ca2+ channel CatSper and affects human sperm function in vitro. What is known already In human sperm, CatSper translates changes of the chemical microenvironment into changes of the intracellular Ca2+ concentration ([Ca2+]i) and swimming behavior. CatSper is promiscuously activated by oviductal ligands, but also by synthetic chemicals that might disturb the fertilization process. It is well known that SSRIs have off-target actions on Ca2+, Na+, and K+ channels in somatic cells. Whether SSRIs affect the activity of CatSper is, however, unknown. Study design, size, duration We studied the action of the seven drugs belonging to the most commonly prescribed class of antidepressants, SSRIs, on resting [Ca2+]i and Ca2+ influx via CatSper in human sperm. The SSRI Sertraline was selected for in-depth analysis of its action on steroid-, prostaglandin-, pH-, and voltage-activation of human CatSper. Moreover, the action of Sertraline on sperm acrosomal exocytosis and penetration into viscous media was evaluated. Participants/materials, setting, methods The activity of CatSper was investigated in sperm of healthy volunteers, using kinetic Ca2+ fluorimetry and patch-clamp recordings. Acrosomal exocytosis was investigated using Pisum sativum agglutinin (PSA) and image cytometry. Sperm penetration in viscous media was evaluated using the Kremer test. Main results and the role of chance Four SSRIs increased [Ca2+]i, two out of which also attenuated ligand-induced Ca2+ influx via CatSper. In contrast, Sertraline decreased [Ca2+]i and almost completely suppressed ligand-induced Ca2+ influx via CatSper. Remarkably, the drug was about four-fold more potent to suppress prostaglandin- versus steroid-induced Ca2+ influx. Sertraline also suppressed alkaline- and voltage-activation of CatSper, indicating that the drug directly inhibits human CatSper. Finally, Sertraline suppressed ligand-induced acrosome reaction and sperm penetration into viscous media. Limitations, reasons for caution This is an in vitro study. Future studies have to assess the physiological relevance in vivo. Wider implications of the findings The off-target action of Sertraline on CatSper in human sperm might impair the fertilization process. In a research setting, Sertraline may be used to selectively inhibit prostaglandin-induced Ca2+ influx. Trial registration number CRU326

Synchronization of the operation of a solid mineral fertilizer spreader and auxiliary machines and mechanisms

The processes of synchronization of the operation of a solid mineral fertilizer spreader and auxiliary machines are described. The methodological approaches are determined. The methodology for calculating and substantiating the parameters and operating modes of the conveyor system for the mineral fertilizer handling is presented. The functional relationships between the parameters of the working bodies of mechanisms and machines involved in the fertilization process and the necessary conditions for their synchronous (uninterrupted) operation are discussed.