Hyperactivated motility of sperm from fertile donors and asthenozoospermic patients before and after treatment with ionophore

Discovery and Characterization of Multiple Classes of Human CatSper Blockers

The cation channel of sperm (CatSper) is a validated target for nonhormonal male contraception, but it lacks selective blockers, hindering studies to establish its role in both motility and capacitation. Via an innovative calcium uptake assay utilizing human sperm we discovered novel inhibitors of CatSper function from a high-throughput screening campaign of 72,000 compounds. Preliminary SAR was established for seven hit series. HTS hits or their more potent analogs blocked potassium-induced depolarization and noncompetitively inhibited progesterone-induced CatSper activation. CatSper channel blockade was confirmed by patch clamp electrophysiology and these compounds inhibited progesterone- and prostaglandin E1-induced hyperactivated sperm motility. One of the hit compounds is a potent CatSper inhibitor with high selectivity for CatSper over hCav1.2, hNav1.5, moderate selectivity over hSlo3 and hERG, and low cytotoxicity and is therefore the most promising inhibitor identified in this study. These new CatSper blockers serve as useful starting points for chemical probe development and drug discovery efforts.

[Sperm hyperactivated motility: influence of the capacitation medium]

OBJECTIVE

Hyperactivation-associated motility is an important marker of capacitation and a prerequisite to fertilization. Computer-Assisted Sperm Analysis (CASA) is a reproducible method that can be used to predict fertilization success, in addition to the migration and survival test. However, published data are contradictory and preparation methods are heterogeneous. Changing one element in the sperm preparation (capacitation medium) may alter its kinetic parameter values.

MATERIAL AND METHOD

This prospective study with two paired series was performed on sperm considered as normal. The sperm preparation was identical up to the second centrifugation, and there after the centrifugate was divided into two groups and suspended either in the capacitating medium Upgraded B2 INRA Medium(R), or in Ferticult Flushing Medium. Measurements were carried out with a Hamilton Thorne Research Analyzer (IVOS v10.9i).

RESULTS

The analysis of the 87 sperm samples included in the study showed differences between the averages of Straight Line Velocity (SLV, p=0.02), Curvilinear Velocity (CLV, p<0.0001), Amplitude of Lateral Head Displacement (ALH, p<0.0001), and algorithmic calculation of the examined hyperactivation (Hyper 5, p<0.0001).

CONCLUSION

The diagnostic validity of hyperactivation motility cannot be dissociated from the preparation conditions. A standardised preparation is a prerequisite for scientific evaluation and validation of this technique. Although higher motility characteristics seem to be desirable in a therapeutic environment, results will have to be validated by clinical tests.

Assessment of hyperactivation, acrosome reaction and motility characteristics of spermatozoa from semen of men of proven fertility and unexplained infertility

Semen from men of proven fertility was compared with that of men with unexplained infertility to determine differences in spermatozoal functions such as hyperactivation and acrosome reaction and spermatozoal motility characteristics. The hyperactivated spermatozoa in both groups could be visualised on the monitor of the Computer Assisted Semen Analyser and they exhibited 'circling', 'thrashing', 'starspin' and 'helical' motility patterns and the mean hyperactivation rates were not significantly different. However, 20% of the men with unexplained infertility did not exhibit hyperactivation compared to only 4% in the fertile group. Furthermore, the semen from infertile men when evaluated for hyperactivation could be categorised into two groups with those having lower hyperactivation (< 10% or < 6% after 4 and 6 h of incubation respectively), forming the first group, and those having a higher hyperactivation rate constituting the second group. In the fertile men such distinct groups were not visible and the percentage hyperactivation ranged from 1 to 16%. No significant differences were observed in the rate of acrosome reaction of fertile and unexplained infertile men. The non-hyperactivated spermatozoa from unexplained infertile men showed a significant increase in path velocity (VAP), curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH) and a decrease in linearity (LIN) and straightness (STR) compared to spermatozoa from fertile men. Furthermore, the hyperactivated spermatozoa from infertile men also showed an increase in progressive velocity (VSL) (only after 2 h of incubation) and LIN and decrease in ALH and beat cross frequency (BCF) compared to spermatozoa from fertile men. The results are discussed in the light of the importance of the above spermatozoal functions and spermatozoal parameters in fertilization.

Functional motion changes during sperm transit to the site of fertilization and in-vitro applications: a review

Continued research to define the parameters of sperm function should aid the evaluation of various approaches in infertility as well as the efficacy of contraceptives for men which do not necessarily achieve azoospermia. Many treatment forms have been advocated for male factor infertility but have yielded little effect. These included, for example, gonadotrophins, clomiphene citrate, the weakly androgenic steroid, mesterolone. Often, improvements in oligoasthenozoospermia that are not related to genital infection, do not attain normozoospermic levels. Owing to lack of success with various treatment modalities, assisted reproductive technology encompassing artificial insemination by husband or donor following in vitro enhancement of sperm function have assumed an important role in male infertility. Agents that have been shown to induce and support sperm capacitation processes such as hyperactivation, could serve an important role. These include human follicular fluid (HFF), maternal serum, fetal cord serum and methyl xanthine derivatives.