Comparisons of sperm quality, morphometry and function among human sperm populations recovered via SpermPrep II filtration, swim-up and Percoll density gradient methods

Cumulative live birth rates after IVF/ICSI cycles with sperm prepared by density gradient centrifugation vs. swim-up: a retrospective study using a propensity score-matching analysis

BACKGROUND

Density gradient centrifugation (DGC) and swim-up (SU) are the two most widely used sperm preparation methods for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). However, existing comparisons of IVF/ICSI outcomes following these sperm preparation methods are insufficient and controversial.

METHODS

This retrospective study included all first autologous IVF and ICSI cycles performed between March 1, 2016, and December 31, 2020 in a single university-based center. A total of 3608 cycles were matched between DGC and SU using propensity score (PS) matching for potential confounding factors at a ratio of 1:1. The primary outcome was the cumulative live birth rate (cLBR) per aspiration.

RESULTS

PS matching provided 719 cycles after DGC and 719 cycles after SU. After adjusting for confounders, the recovery rate, progressive motility rate after sperm preparation, fertilization rate, good-quality embryo rate, and blastocyst formation rate were similar between the DGC and SU groups. The cLBR (odds ratio [OR] = 1.143, 95% confidence interval [CI]: 0.893-1.461) and LBR per transfer (OR = 1.082, 95% CI: 0.896-1.307) were also not significantly different between the groups. Furthermore, no significant differences were found in all of the laboratory and clinical outcomes following conventional IVF or ICSI cycles between the two groups. However, a significantly higher fertilization rate (β = 0.074, 95% CI: 0.008-0.140) was observed when using poor-quality sperm in the DGC group than in the SU group.

CONCLUSIONS

Sperm preparation using DGC and SU separately resulted in similar IVF/ICSI outcomes. Further studies are warranted to compare the effects of these methods on IVF/ICSI outcomes when using sperm from subgroups of different quality.

Comparison of the structure of chinchilla sperm isolated from semen and from the tail of the epididymis

Sperm cells isolated from the tail of the epididymis and from the semen of the same individuals were analysed. The use of silver nitrate to stain sperm cells isolated from the tail of the epididymis made it possible to identify structures that were not visible in the sperm from semen. Silver nitrate very clearly distinguished the acrosomal and distal parts of the sperm head. Following silver nitrate staining, the sperm isolated from the tail of the epididymis were characterized by dark 'collars' in the distal part of the head. These 'collars' are not visible in the sperm cells isolated from semen. The results of the study indicate differences in the dimensions of sperm isolated from the tail of the epididymis and sperm in semen. Sperm isolated from the tail of the epididymis had smaller heads, despite their longer length, and had longer midpieces and tails than ejaculate sperm. Silver nitrate staining is a simple and fast technique. Silver nitrate makes it possible to identify the acrosome and post-acrosomal region of the sperm head and to clearly identify the midpiece. Therefore, it can be successfully used to supplement routine techniques for evaluating sperm morphology or as an independent technique.

Effects of a micronutrient supplementation combined with a phosphodiesterase type 5 inhibitor on sperm quantitative and qualitative parameters, percentage of mature spermatozoa and sperm capacity to undergo hyperactivation: A randomised controlled trial

The main objective of this study was to evaluate the effects of a micronutrient supplementation (MS) combined with avanafil on sperm function. Oligoasthenospermic men (n = 217) were treated daily for 90 days with either an MS (45 men, Group A), l-carnitine (44 men, Group B), MS plus avanafil (43 men, Group C) or avanafil (43 men, Group D); another group of 42 men with oligoasthenospermia (Group E) received no treatment. Sperm parameters were evaluated before and after the end of treatment in each Group A, B, C and D respectively. The same sperm parameters were measured in each participant of Group E before and at the 90-day experimental period. Within Groups A, C or D, the total percentage of motile spermatozoa, the hypoosmotic swelling test (HOST) result and the percentage of hyperactivated spermatozoa after incubation under conditions known to induce sperm capacitation were significantly greater after MS or MS plus avanafil treatment, or avanafil treatment than before the respective treatment. We suggest that MS or MS plus avanafil combined administration or avanafil alone improves sperm membrane permeability with an overall result improvement in sperm motility, outcome of HOST and increase in the percentage of hyperactivated spermatozoa.

Importance of sperm morphology during sperm transport and fertilization in mammals

After natural or artificial insemination, the spermatozoon starts a journey from the site of deposition to the place of fertilization. However, only a small subset of the spermatozoa deposited achieves their goal: to reach and fertilize the egg. Factors involved in controlling sperm transport and fertilization include the female reproductive tract environment, cell-cell interactions, gene expression, and phenotypic sperm traits. Some of the significant determinants of fertilization are known (i.e., motility or DNA status), but many sperm traits are still indecipherable. One example is the influence of sperm dimensions and shape upon transport within the female genital tract towards the oocyte. Biophysical associations between sperm size and motility may influence the progression of spermatozoa through the female reproductive tract, but uncertainties remain concerning how sperm morphology influences the fertilization process, and whether only the sperm dimensions per se are involved. Moreover, such explanations do not allow the possibility that the female tract is capable of distinguishing fertile spermatozoa on the basis of their morphology, as seems to be the case with biochemical, molecular, and genetic properties. This review focuses on the influence of sperm size and shape in evolution and their putative role in sperm transport and selection within the uterus and the ability to fertilize the oocyte.

Comparative study on density gradients and swim-up preparation techniques utilizing neat and cryopreserved spermatozoa

AIM

To 1) compare post-wash and post-thaw parameters of sperm processed with PureSperm density gradient technique and swim-up method; and 2) test the efficacy of two commonly available density gradient media PureSperm and ISolate.

METHODS

This prospective study used semen specimens from 22 patients. Specimens from nine patients were processed by both PureSperm density gradient and swim-up method. These specimens were then cryopreserved. Thirteen specimens were processed by both PureSperm (40 % and 80 %) and Isolate (50 % and 90 %) double density gradient techniques. The two fractions processed by both PureSperm and swim-up were analyzed for post-wash sperm characteristics. Post-thaw analysis was done after 24 hours. Sperm fractions obtained after processing with PureSperm and ISolate were compared for post-wash sperm characteristics and ROS levels.

RESULTS

Specimens prepared with PureSperm had significantly higher median total motile sperm counts (TMSC) (32.2 x 10(6) vs. 17.6 x 10(6)), recovery rates (69.2 % vs. 50.0 %), and longevity at 4 hours (83.0 % vs. 55.0 %) compared to specimen prepared by swim-up. Post-thaw specimens also had a higher recovery and longevity at 4 hours with PureSperm as compared to the swim-up. Semen specimens processed by PureSperm had significantly higher total sperm count, TMSC, and percentage recovery rates (30.0 % vs. 19.7 %) than ISolate.

CONCLUSION

Semen quality is better preserved in fresh and cryopreserved semen prepared with PureSperm density gradient compared to swim-up. A significant enrichment of sperm is observed with PureSperm compared to ISolate. Higher recovery rates of mature motile sperm obtained after PureSperm sperm preparation may be beneficial for successful ART.

Effects of paternal cigarette smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation in rats

We evaluated the effects of paternal smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation. Rats of group A were exposed to cigarette smoke for 10 weeks. Rats of group B were exposed to the smoke of incense sticks for 10 weeks. Rats of group C served as a control group. Rats of group D were exposed to cigarette smoke for 7 weeks only. Experimental period was 10 weeks in all groups. At the end of the experimental period serum testosterone responses to human chorionic gonadotropin stimulation, androgen-binding protein activity in testicular cytosols, epididymal sperm motility, and oocyte fertilization rate, oocyte cleavage rate, and blastocyst development rate after in vitro fertilization (IVF) trials were significantly smaller in group A compared with groups B and C. In contrast, fertilization rate, cleavage rate, and blastocyst development rate after intracytoplasmic sperm injection (ICSI) procedures were not significantly different among groups A, B, C, and D. Both after IVF trials and ICSI techniques, the proportion of the alive offspring to the number of transferred oocytes was significantly smaller in group A than in groups B and C. Cigarette smoke-exposure results in a secretory deficiency of Leydig and Sertoli cells leading to an impaired epididymal sperm maturation process and diminished capacity of spermatozoa to penetrate oocytes. In addition paternal cigarette smoke exposure affects the embryonic ability for implantation.