Relationship between Semenogelins bound to human sperm and other semen parameters and pregnancy outcomes

Abstract

BackgroundSemenogelins (SEMGs) are major components of human seminal vesicle secretions. Due to SEMG’s sperm-motility inhibitor, a significant negative correlation between sperm motility and the proportion of SEMG-bound spermatozoa (SEMG+) was found in asthenozoospermic patients. SEMGs also show intrinsic inhibitory capability for sperm capacitation; however, studies on actual clinical specimens have not been conducted.MethodsTo reveal the relationship between SEMGs and the fertilizing capacity of sperm from male infertile patients who are not restricted to asthenozoospermia, we measured the proportion of SEMG+ in the spermatozoa of 142 male infertile patients. The pregnancy outcomes in partners of these patients were retrospectively analyzed using questionnaires.ResultsAmong examined semen parameters, only the total SEMG-unbound sperm count showed a tendency to be different between the spontaneous pregnancy or intra-uterine-insemination-pregnancy groups and in-vitro-fertilization- or intracytoplasmic-sperm-injection-pregnancy groups. It was elevated in the former group, which includes patients who used in vivo fertilization.ConclusionsThe total SEMG-unbound sperm count would be a relevant parameter for in vivo fertilization. This result suggests that SEMGs inhibit ectopic capacitation before sperm reach the fertilization site and that the number of total SEMG-unbound sperm is a parameter directly linked to the possibility of in vivo fertilization.Electronic supplementary materialThe online version of this article (doi:10.1186/s12610-017-0059-6) contains supplementary material, which is available to authorized users.

Does the Pre-Ovulatory Pig Oviduct Rule Sperm Capacitation In Vivo Mediating Transcriptomics of Catsper Channels?

“…Seminal vesicles are believed to be responsible for the release of these decapacitating molecules that bind to the sperm membrane to inhibit capacitation. However, this phenomenon has been observed only in human and mice in vitro experiments that mixed capacitated spermatozoa with SP or candidate decapacitation factors [68][69][70]. In the pig, in vivo studies suggest that SP proteins are potentially involved in regulating sperm fertility [71,72].…”

Mechanism of semen liquefaction and its potential for a novel non-hormonal contraception†

“…In this context, a study by Yamakasi et al. [ 12 ] also indicated that patients with higher number of SEMG-unbound spermatozoa can achieve successful pregnancy, making total SEMG-unbound sperm count a relevant parameter for in vivo fertilization. Additionally, SEMG peptides are also involved in other biological functions such as increasing sperm hyaluronidase activity [ 13 ], antibacterial activity [ 14 ], hyperpolarization, and permeability of sperm plasma membrane [ 15 ].…”

“…In Chinese–Han male population, the SEMG1 variant rs2301366 was associated with abnormal semen parameters such as semen volume, sperm concentration, sperm number per ejaculate, and sperm motility and more susceptible to infertility [ 63 ]. In another study, a negative correlation between sperm motility and the proportion of SPMI (of SEMG sequence)-bound spermatozoa was also found in male subjects including infertile normozoospermics, asthenozoospermics, and oligozoospermics [ 12 ]. These findings suggest that SEMGs remained on the sperm surface post-liquefaction might account for impaired sperm motility in infertile men.…”

Human Semenogelin 1 Promotes Sperm Survival in the Mouse Female Reproductive Tract

“…Although the mechanism of acceptance of SEMGs has not been fully elucidated, binding of SEMG1 to sperm via adaptor protein EPPIN has been shown [22,23]. Moreover, the SEMG-unbound sperm count is expected to be a relevant parameter for in vivo fertilization based on clinical studies on infertile couples using assisted reproductive technology [24].…”