Incubation of spermatozoa from asthenozoospermic semen samples with pentoxifylline and 2-deoxyadenosine: variability in hyperactivation and acrosome reaction rates

An Alternative Application of Magnetic-Activated Cell Sorting: CD45 and CD235a Based Purification of Semen and Testicular Tissue Samples

Magnetic activated cell sorting (MACS) is a well-known sperm selection technique, which is able to remove apoptotic spermatozoa from semen samples using the classic annexinV based method. Leukocytes and erythrocytes in semen samples or in testicular tissue processed for in vitro fertilization (IVF) could exert detrimental effects on sperm. In the current study, we rethought the aforementioned technique and used magnetic microbeads conjugated with anti-CD45/CD235a antibodies to eliminate contaminating leukocytes and erythrocytes from leukocytospermic semen samples and testicular tissue samples gained via testicular sperm extraction (TESE). With this technique, a 15.7- and a 30.8-fold reduction could be achieved in the ratio of leukocytes in semen and in the number of erythrocytes in TESE samples, respectively. Our results show that MACS is a method worth to reconsider, with more potential alternative applications. Investigations to find molecules labeling high-quality sperm population and the development of positive selection procedures based on these might be a direction of future research.

Tissue and sperm handling before assisted reproductive technology (ART): A systematic review

Objective

: To explore the medical literature on techniques of tissue and sperm handling after surgical retrieval for intracytoplasmic sperm injection (ICSI).

Methods

: A search was performed in PubMed and Google Scholar databases, according to a modified Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guideline, considering the studies investigating tissue handling and sperm selection techniques for ICSI.

Results

: Overall, 42 articles were included in this study, investigating sample handling, methods for sperm selection, and the use of chemical compounds to improve sperm motility and fertilisation rates.

Conclusion

: The ideal sperm handling method should provide a high sperm count, high vitality and appropriate sperm function, without side-effects. In this review the most common and useful techniques are described and the best combination strategies discussed in clinical scenarios.

Seminal vesicle sperm aspiration from wounded warriors

OBJECTIVE

To assess whether seminal vesicle sperm aspiration (SVSA) is an option for wounded warriors with severe genital and testicular injuries, with the goal of cryopreservation to use in future assisted reproductive technology (ART) cycles.

DESIGN

Retrospective case series.

SETTING

Tertiary care military hospital.

PATIENT(S)

Six wounded warriors.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Seminal vesicle fluid analysis after harvest, after thaw analysis, fertilization rates, pregnancy rates (PRs), live birth.

RESULT(S)

Six patients with lower extremity, pelvic, and genital injuries from dismounted improvised explosive devices underwent SVSA within 5-12 days of the initial injury. Sperm retrieved were analyzed (volume, 0.4-1.8 mL; concentration, 40-2,200 K; motility, 0-5%), washed, and cryopreserved. Two patients underwent IVF/intracytoplasmic sperm injection (ICSI) cycles using their samples. In one couple, fertilization rate was 38%. One grade V embryo was transferred with a negative pregnancy test. The second couple underwent two cycles. In their first cycle, fertilization rate was 44%, with one blastocyst transferred and a negative pregnancy test. In the second cycle, fertilization rate was 47%. Two blastocysts were cryopreserved due to ovarian hyperstimulation syndrome (OHSS) concerns. One blastocyst was later transferred in a frozen cycle resulting in a live birth.

CONCLUSION(S)

The SVSA is a reasonable option to retrieve sperm in wounded warriors or trauma patients with extensive genital injuries.

The clinical significance of calcium-signalling pathways mediating human sperm hyperactivation

STUDY QUESTION

What is the prevalence of defects in the Ca²⁺-signalling pathways mediating hyperactivation (calcium influx and store mobilization) among donors and sub-fertile patients and are they functionally significant, i.e. related to fertilization success at IVF?

SUMMARY ANSWER

This study identifies, for the first time, the prevalence of Ca²⁺ store defects in sperm from research donors, IVF and ICSI patients. It highlights the biological role and importance of Ca²⁺ signalling (Ca²⁺ store mobilization) for fertilization at IVF.

WHAT IS KNOWN ALREADY

Sperm motility and hyperactivation (HA) are important for fertility, mice with sperm incapable of HA are sterile. Recently, there has been significant progress in our knowledge of the factors controlling these events, in particular the generation and regulation of calcium signals. Both pH-regulated membrane Ca²⁺ channels (CatSper) and Ca²⁺ stores (potentially activating store-operated Ca²⁺ channels) have been implicated in controlling HA.

STUDY DESIGN, SIZE, AND DURATION

This was a prospective study examining a panel of 68 donors and 181 sub-fertile patients attending the Assisted Conception Unit, Ninewells Hospital Dundee for IVF and ICSI. Twenty-five of the donors gave a second sample (∼4 weeks later) to confirm consistency/reliability of the recorded responses. Ca²⁺ signalling was manipulated using three agonists, NH₄Cl (activates CatSper via pH), progesterone (direct activation of CatSper channels, potentially enhancing mobilization of stored Ca²⁺ by CICR) and 4-aminopyridine (4-AP) (effect on pH equivalent to NH₄Cl and mobilizes stored Ca²⁺). The broad-spectrum phosphodiesterase inhibitor 3-isobutyl-1-methyxanthine (IBMX), a potent activator of HA was also used for comparison. For patient samples, an aliquot surplus to requirements for IVF/ICSI treatment was examined, allowing direct comparison of Ca²⁺ signalling and motility data with functional competence of the sperm.

MATERIALS, SETTING, METHODS

The donors and sub-fertile patients were screened for HA (using CASA) and changes in intracellular Ca²⁺ were assessed by loading with Fura-2 and measuring fluorescence using a plate reader (FluoStar).

MAIN RESULTS AND THE ROLE OF CHANCE

The relative efficacy of the stimuli in inducing HA was 4-AP >> IBMX > progesterone. NH₄Cl increased [Ca²⁺]_i similarly to 4-AP and progesterone but did not induce a significant increase in HA. Failure of samples to generate HA (no significant increase in response to stimulation with 4-AP) was seen in just 2% of research donors but occurred in 10% of IVF patients (P = 0.025). All donor samples generated a significant [Ca²⁺]_i increase when stimulated with 4-AP but 3.3% of IVF and 28.6% of ICSI patients failed to respond. Amplitudes of HA and [Ca²⁺]_i responses to 4-AP were correlated with fertilization rate at IVF (P= 0.029; P = 0.031, respectively). Progesterone reliably induced [Ca²⁺]_i responses (97% of donors, 100% of IVF patients) but was significantly less effective than 4-AP in inducing HA. Twenty seven per cent of ICSI patients failed to generate a [Ca²⁺]_i response to progesterone (P= 0.035). Progesterone-induced [Ca²⁺]_i responses were correlated with fertilization rate at IVF (P= 0.037) but induction of HA was not. In donor samples examined on more than one occasion consistent responses for 4-AP-induced [Ca²⁺]_i (R² = 0.97) and HA (R² = 0.579) were obtained. In summary, the data indicate that defects in Ca²⁺ signalling leading to poor HA do occur and that ability to undergo Ca²⁺ -induced HA affects IVF fertilizing capacity. The data also confirm that release of stored Ca²⁺ is the crucial component of Ca²⁺ signals leading to HA and that Ca²⁺ store defects may therefore underlie HA failure.

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro study of sperm function. While the repeatability of the [Ca²⁺]_i and HA responses in samples from the same donor were confirmed, data for patients were from 1 assessment and thus the robustness of the failed responses in patients’ needs to be established. The focus of this study was on using 4AP, which mobilizes stored Ca²⁺ and is a potent inducer of HA. The n values for other agonists, especially calcium assessments, are smaller.

WIDER IMPLICATIONS OF THE FINDINGS

Previous studies have shown a significant relationship between basal levels of HA, calcium responses to progesterone and IVF fertilization rates. Here, we have systematically investigated the ability/failure of human sperm to generate Ca²⁺ signals and HA in response to targeted pharmacological challenge and, related defects in these responses to IVF success. [Ca²⁺]_i signalling is fundamental for sperm motility and data from this study will lead to assessment of the nature of these defects using techniques such as single-cell imaging and patch clamping.

STUDY FUNDING/COMPETING INTEREST(S)

Resources from a Wellcome Trust Project Grant (#086470, Publicover and Barratt PI) primarily funded the study. The authors have no competing interests.

Laboratory processing and intracytoplasmic sperm injection using epididymal and testicular spermatozoa: what can be done to improve outcomes?

There are two main reasons why sperm may be absent from semen. Obstructive azoospermia is the result of a blockage in the male reproductive tract; in this case, sperm are produced in the testicle but are trapped in the epididymis. Non-obstructive azoospermia is the result of severely impaired or non-existent sperm production. There are three different sperm-harvesting procedures that obstructive azoospermic males can undergo, namely MESA (microsurgical epididymal sperm aspiration), PESA (percutaneous epididymal sperm aspiration), and TESA (testicular sperm aspiration). These three procedures are performed by fine-gauge needle aspiration of epididymal fluid that is examined by an embryologist. Additionally, one technique, called TESE (testicular sperm extraction), is offered for males with non-obstructive azoospermia. In this procedure, a urologist extracts a piece of tissue from the testis. Then, an embryologist minces the tissue and uses a microscope to locate sperm. Finding sperm in the testicular tissue can be a laborious 2- to 3-hour process depending on the degree of sperm production and the etiology of testicular failure. Sperm are freed from within the seminiferous tubules and then dissected from the surrounding testicular tissue. It is specifically these situations that require advanced reproductive techniques, such as ICSI, to establish a pregnancy. This review describes eight different lab processing techniques that an embryologist can use to harvest sperm. Additionally, sperm cryopreservation, which allows patients to undergo multiple ICSI cycles without the need for additional surgeries, will also be discussed.

Comparative flow cytometric analysis of the human sperm acrosome reaction using CD46 antibody and lectins

PURPOSE

Our purpose was to determine the most suitable marker for the human sperm acrosome reaction, based on detection of CD46 antibody binding compared with lectin binding.

METHODS

Flow cytometric analysis of CD46 antibody versus lectins (PNA, PSA, and Con A) was used to quantify the acrosome reaction of human sperm.

RESULTS

Neither PSA nor Con A was able to detect significant changes in the spontaneous and ionophore-induced acrosome reactions compared to CD46 antibody. However, PNA was found to exhibit a binding pattern similar to that observed with CD46 and could be used to quantify measurable changes in acrosomal response to ionophore, albeit of a lower magnitude than the responses detected by CD46.

CONCLUSIONS

We conclude that PNA binds to the inner acrosomal membrane of acrosome-reacted sperm and is suitable for use as a marker of the acrosome reaction by flow cytometry. Data are presented which clarify the assessment of the acrosome reaction when CD46 and lectins are used.

Could in vitro fertilization with a modified sperm preparation technique be an option to micromanipulations?

PURPOSE

This study evaluated the efficiency of in vitro fertilization with a modified sperm preparation technique for male infertility, to avoid systematic recourse to ICSI.

METHODS

The sperm function stimulants pentoxifylline, 2-deoxyadenosine, and follicular fluid were used during the sperm preparation of IVF trials for two groups of patients: couples with long-standing infertility and previous IVF failures and couples with male-factor infertility scheduled for their first treatment.

RESULTS

Forty-nine attempts were performed in the first group. The overall fertilization rate (percentage of zygotes with two pronuclei 18 hr after sperm insemination) was 30% and the clinical pregnancy rate per transfer was 33%. For the second group, 30 attempts were performed. The fertilization rate was 29.6% and the clinical pregnancy rate was 62.5% per transfer. The total number of recovered motile sperm appears to be a significant parameter: a cutoff value of 0.25 million motile sperm recovered after capacitation treatment has a good prognostic value for choosing between IVF with sperm enhancers and ICSI.

CONCLUSIONS

The described modified IVF could constitute an alternative to the systematic use of ICSI.

Successful use of pentoxifylline in male-factor infertility and previous failure of in vitro fertilization: a prospective randomized study

OBJECTIVE

Our objective was to determine whether the use of pentoxifylline (PF) would improve the in vitro fertilization (IVF) rate and outcome in couples with male factor infertility and previous failure of fertilization in vitro.

DESIGN

This prospective randomized controlled study was conducted in an assisted conception unit.

MATERIALS AND METHODS

Forty-nine couples with previous failed fertilization in vitro attributable to male factor or male-factor infertility without previous IVF were recruited for the study. Controlled ovarian hyperstimulation was performed using a combination of gonadotropin releasing hormone agonist and human menopausal gonadotropin. Oocytes of the same grade and maturity were inseminated with spermatozoa treated with PF or control spermatozoa. A maximum of three embryos was replaced after 48 hr and all other embryos were cryopreserved. Pregnancy outcome was followed up and evidence of fetal or neonatal anomalies reported.

RESULTS

A significantly higher fertilization rate occurred in the group where oocytes were inseminated with spermatozoa treated with PF compared with controls (56.3 versus 30.7%; P < 0.05). Fertilization occurred in 45 of the 49 cycles (92%). In seven cycles, only the oocytes that were inseminated with spermatozoa treated with PF fertilized, in contrast to only one cycle where the oocytes inseminated with control sperm fertilized (P < 0.05). Fifty-seven PF and 31 control embryos were replaced and 11 clinical pregnancies occurred. Three of the pregnancies occurred in the seven cycles in which only PF embryos were replaced, one in the single cycle where control embryos were replaced and seven from the 37 cycles in which both PF and control embryos were replaced. There was no evidence of congenital malformations in any of the offsprings resulting from this study.

CONCLUSION

This study suggests that PF improves the fertilization rate and outcome in couples with male factor infertility and poor fertilization rates. This study does not suggest any increase in teratogenicity or evidence of congenital malformations in pregnancies following IVF cycles where PF was used.

Sperm stimulants can improve fertilization rates in male-factor cases undergoing IVF to the same extent as micromanipulation by partial zona dissection (PZD) or subzonal sperm insemination (SUZI): a randomized controlled study

PURPOSE

Our purpose was to evaluate the efficacy of direct insemination (IVF), micromanipulation by partial zona dissection (PZD), and subzonal sperm insemination (SUZI) using sperm-treated with pentoxifylline (PF) +/- 2-deoxyadenosine (2DA).

RESULTS

The overall fertilization rate achieved was similar for all three fertilization techniques (33.1, 30.2, and 26.9% for IVF, SUZI, and PZD, respectively). Patients who had reduced fertilization in previous IVF attempts showed improved fertilization with sperm stimulants, either PF alone or PF in combination with 2DA in standard IVF. In certain cases, SUZI or PZD gave significantly improved fertilization rates in comparison to IVF.

CONCLUSION

Selective use of sperm stimulants in IVF can achieve fertilization for the majority of male-factor cases. However, PZD and SUZI techniques are useful, especially when sperm stimulants fail to achieve fertilization or achieve poor fertilization in direct insemination.