Standards in semen examination: publishing reproducible and reliable data based on high-quality methodology

Biomedical science is rapidly developing in terms of more transparency, openness and reproducibility of scientific publications. This is even more important for all studies that are based on results from basic semen examination. Recently two concordant documents have been published: the 6th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, and the International Standard ISO 23162:2021. With these tools, we propose that authors should be instructed to follow these laboratory methods in order to publish studies in peer-reviewed journals, preferable by using a checklist as suggested in an Appendix to this article.

P-044 Abnormal sperm morphology, so what? The clinical outcome of medical assisted reproduction is not affected by 100% teratospermic semen samples

Study question

What is the success rate (clinical outcome) in medical assisted reproduction (MAR) when 0% normal spermatozoa forms are observed using strict morphology criteria (SMC)?

Summary answer

Strict criteria morphology has no predictive value for the clinical outcome of MAR. Absence of normal morphology spermatozoa does not preclude high cumulative pregnancy rates.

What is known already

Many studies have questioned the clinical value of sperm morphology since no effect on treatment outcome is apparent when sperm samples with <4% normal forms are used. However, data evaluating treatment outcome when 0% normal sperm at diagnose (evaluated by strict morphology criteria, WHO 2010) scarce. While teratozoospermia values are known to have a negative correlation with fertilization per cycle, data on cumulative ongoing pregnancy rates (COPR) or live birth rates (LBR) are missing in this selected group.

Study design, size, duration

This is a retrospective analysis (January 2010-June 2021) of the clinical outcome for couples when the male partner presents with 0% normal morphology (WHO 2010) at diagnostic semen analysis. Cases with 100% globozoospermia, cilia abnormalities or other MMAF phenotypes were excluded. Depending on the total progressively motile sperm count (TPMSC), couples were referred for MAR. The primary outcome presented is COPR/treatment and LBR/couple. Secondary outcomes were total fertilization failure (TFF) and mean fertilization rate (FR).

Participants/materials, setting, methods

All 193 cases included in this study presented with 100% teratozoospermia, as evaluated by two independent technicians following WHO 2010 manual recommendations. Couples were treated with IUI,IVF or ICSI depending on TPMSC at diagnosis. A total of 17 couples underwent 68 IUI treatments, 20 couples underwent 36 IVF ovum-pickups (OPU) (with respectively fresh embryo transfer (ET) and frozen ET, FET); 156 couples underwent 394 ICSI-OPU (with respectively fresh-ET and FET). Cumulative-OPR per treatment/couple is presented.

Main results and the role of chance

From the 17 couples undergoing IUI (mean 4 IUI cycles/couple; with or without mild ovarian stimulation) 3 ongoing pregnancies were reported (all singletons; 18% LBR per couple). Twenty IVF couples (mean 1.8 OPUs/couple) resulted in a total of 13 ongoing pregnancies (12 singletons, 1 twin pregnancy), therefore, the LBR per IVF-couple was 65%. In six cycles a TFF was observed even with sufficient motile sperm during insemination (5x with TPMSC >5 x 10^6/ml). If TFF was observed after IVF cycle, then ICSI was performed in the next cycle. The IVF mean %FR using 100% teratozoospermic samples was 54%, compared to 58% in cases with >1% normal forms.

Regarding ICSI, 156 couples underwent a total of 377 cycles (mean of 2.4 OPUs/couple). These treatments resulted in a total of 357 fresh-ET and 458 FET. A total of 103 couples achieved 154 ongoing pregnancies (146 singletons, 7 twins), therefore the COPR was 39%/cycle and LBR was 66%/couple. In 13 cycles (3.4%) TFF was observed and in 15 cases the fertilization rate was <20%. The mean FR with ICSI using teratozoospermic samples was 55%. Comparingly, using samples with >1% normal morphology, the laboratory mean for FR is 68% and 3.7% for TFF.

Limitations, reasons for caution

This is a retrospective study and not matched case-control cohort was used in this analysis. Not all couples have completed 3 complete IVF/ICSI cycles. As not all frozen embryos have been transferred, cumulative pregnancy rates might be higher than the rates reported here.

Wider implications of the findings

The data presented here confirms the limited value of the actual strict criteria for sperm morphology evaluation. Morphology is important for identification of sporadic sperm samples with atypical malformations such as globozoospermia, MMAF and other aberrant forms of a genetic origin, however SMC evaluation and interpretation should be reconsidered

Trial registration number

N.A.

Human and animal fertility studies in cystinosis reveal signs of obstructive azoospermia, an altered blood-testis barrier and a subtherapeutic effect of cysteamine in testis

Cystinosis is an inherited metabolic disorder caused by autosomal recessive mutations in the CTNS gene leading to lysosomal cystine accumulation. The disease primarily affects the kidneys followed by extra-renal organ involvement later in life. Azoospermia is one of the unclarified complications which are not improved by cysteamine, which is the only available disease-modifying treatment. We aimed at unraveling the origin of azoospermia in cysteamine-treated cystinosis by confirming or excluding an obstructive factor, and investigating the effect of cysteamine on fertility in the Ctns^-/- mouse model compared with wild type. Azoospermia was present in the vast majority of infantile type cystinosis patients. While spermatogenesis was intact, an enlarged caput epididymis and reduced levels of seminal markers for obstruction neutral α-glucosidase (NAG) and extracellular matrix protein 1 (ECM1) pointed towards an epididymal obstruction. Histopathological examination in human and mouse testis revealed a disturbed blood-testis barrier characterized by an altered zonula occludens-1 (ZO-1) protein expression. Animal studies ruled out a negative effect of cysteamine on fertility, but showed that cystine accumulation in the testis is irresponsive to regular cysteamine treatment. We conclude that the azoospermia in infantile cystinosis is due to an obstruction related to epididymal dysfunction, irrespective of the severity of an evolving primary hypogonadism. Regular cysteamine treatment does not affect fertility but has subtherapeutic effects on cystine accumulation in testis.

O-149 Evaluation of structural problems in the application of strict criteria for sperm morphology assessment

Study question

Which criteria, described by WHO 2010, cause most problems during sperm morphology assessment and lead to outcome variation in a national external quality control program?

Summary answer

Assessment of head ovality, regularly contoured head, regularly contoured midpiece and alignment of major axis of midpiece and head lead to the most variation.

What is known already

Morphology assessment of spermatozoa is known as a rather difficult part of semen analysis. Over the past 40 years, morphological criteria became stricter and reference values changed significantly, leading to a 4% lower reference value for normal/typical morphology in 2010. This has consequences for the statistical power of the analysis. Moreover, many laboratories do not use the staining method as advised by the WHO and are getting stricter and stricter in the application of the criteria. Improvement of the assay is therefore necessary. In this study, as a first step, variation in the use of the strict criteria is evaluated.

Study design, size, duration

Data from the Dutch external quality control (EQC) program were evaluated in this retrospective study over the period 2015 – 2020. The program consists of four rounds per year and includes the assessment of three photos of Papanicolaou stained spermatozoa. These spermatozoa were dichotomously judged (normal/abnormal) on 14 morphological criteria (WHO manual, 2010). Consensus results of three experts served as reference. In total, variation over results of 72 photos (1008 values) was analysed.

Participants/materials, setting, methods

Participants were staff members from Dutch laboratories (1 member per lab per round) that perform semen analysis. The outcomes of the participants were tested for variation per criterion, both over the entire 6-year period and for trends during this period. To gain insight in the influence of “time”, three photos were provided three times (in 2015/2018/2020) and six photos were provided twice (in 2016/2018 and 2018/2020). Setup was blinded to both participants and experts.

Main results and the role of chance

In the period 2015 – 2020, 88 – 103 laboratories participated in the EQC program. Of these laboratories, 40 – 60 took part in the photo evaluation. Variation per criterion was expressed in categories green, orange and red, with resp. >90%, 60-90% and <60% agreement between the participants. Overall, variation was in 57% in category green, 37% orange and 6% red. Head ovality, regularity of head contours, regularity of midpiece contours and alignment of the major axis of midpiece and head lead to the most variation. For these criteria, resp. 14, 17, 10 and 17% were in the category red and resp. 50, 47, 71 and 64% in category orange. Lowest variation was found for acrosomal vacuoles, excessive residual cytoplasm, tail thickness and tail length with resp. 76, 77, 94, 85% in category green. Trend analysis lead to similar conclusions: most criteria show a slightly positive trend, but head ovality and regularity of head and midpiece show a stable or declining trend. Three photos were used in three rounds and six photos in two rounds. In 26 (8.8%) cases, shifts towards higher (5) or lower (21) variation were found. Experts changed their opinion in 3 (1%) cases.

Limitations, reasons for caution

Results are dependent on the morphology of the spermatozoa (magnitude of abnormalities) and of the photo quality.

Wider implications of the findings

The definitions of the criteria need to be better explained and trained, especially for ovality of the head, regularity of the midpiece and overlap of the longitudinal axes of midpiece and head. Moreover, explanation of the criteria in the light of physiology will probably lead to better evaluations by participants.

Trial registration number

Not Applicable

Reducing Inter-Laboratory Differences between Semen Analyses Using Z Score and Regression Transformations

BACKGROUND

Standardization of the semen analysis may improve reproducibility. We assessed variability between laboratories in semen analyses and evaluated whether a transformation using Z scores and regression statistics was able to reduce this variability.

MATERIALS AND METHODS

We performed a retrospective cohort study. We calculated between-laboratory coefficients of variation (CVB) for sperm concentration and for morphology. Subsequently, we standardized the semen analysis results by calculating laboratory specific Z scores, and by using regression. We used analysis of variance for four semen parameters to assess systematic differences between laboratories before and after the transformations, both in the circulation samples and in the samples obtained in the prospective cohort study in the Netherlands between January 2002 and February 2004.

RESULTS

The mean CVBwas 7% for sperm concentration (range 3 to 13%) and 32% for sperm morphology (range 18 to 51%). The differences between the laboratories were statistically significant for all semen parameters (all P<0.001). Standardization using Z scores did not reduce the differences in semen analysis results between the laboratories (all P<0.001).

CONCLUSION

There exists large between-laboratory variability for sperm morphology and small, but statistically significant, between-laboratory variation for sperm concentration. Standardization using Z scores does not eliminate between-laboratory variability.

Rydberg state ionization by half-cycle-pulse excitation: strong kicks create slow electrons

The asymptotic velocity distribution of electrons ionized in half-cycle-pulse excitation of high Rydberg states (n=34), placed in a static electric field, is studied using electron velocity-map imaging. At weak half-cycle pulse strengths, the electrons escape over the saddle point in the potential. For strong half-cycle pulses, the electrons are emitted in the direction of the field kick. The much slower and less intense half cycle of opposite polarity, which necessarily follows the main half-cycle pulse, strongly affects the momentum distribution and reduces the excess energy of the electrons significantly.

Assessment of DNA fragmentation of spermatozoa that were surgically retrieved from men with obstructive azoospermia

OBJECTIVE

To determine the degree of DNA fragmentation in spermatozoa of men with obstructive azoospermia or anejaculation compared with that of ejaculated spermatozoa from fertile donors.

DESIGN

Observational study. SETTING; University Medical Center St. Radboud, Nijmegen. The Netherlands.

PATIENT(S)

Forty-one patients with obstructive azoospermia or anejaculation and 10 fertile donors.

MAIN OUTCOME MEASURE(S)

Sperm samples were obtained surgically from the epididymis or testis of men with azoospermia or anejeculation and by ejaculation in fertile patients. DNA fragmentation was analyzed in the total sample and in a motile fraction that was isolated as in routine ICSI procedures. DNA breaks were measured by using the TdT-mediated dUTP nick-end labeling assay.

RESULT(S)

A higher percentage of cells with DNA breaks was found in men with obstructive azoospermia or anejaculation compared with donors (mean, 18.9% vs. 6.2%). A significant lower degree of DNA fragmentation was observed in the motile fraction from patients compared with donors (0.4% vs. 0.6%).

CONCLUSION(S)

High percentages of cells with DNA damage were found in sperm samples from men with obstructive azoospermia or anejaculation, but a very low frequency of damage to the DNA was observed in the motile fraction. In an ICSI setting, the use of motile sperm retrieved from epididymis or testis of men with obstructive azoospermia does not seem to pose a higher genetic risk to the progeny than does use of motile ejaculated sperm.

Human follicular fluid adverses hamster spermatozoa motility

To determine the optimal conditions for in vitro spermatozoa vitality, human and hamster spermatozoa were incubated at 37 degrees C in T6 medium supplemented with different biologic fluids (10% v/v). The fluids tested were human serum (HUS), hamster serum (HAS), and human follicular fluid (HUF). After incubation the spermatozoa were investigated for their qualitative and quantitative motility. Human spermatozoa maintained a good vitality in all fluids tested (approximately 25% motility after 18-h incubation). The hamster spermatozoa had after an incubation of 4 h a motility of 28.4% in HUS, 14.2% in HAS, and 2.2% in HUF. The quality of the motility was also extremely low in HUF, whereas it was adequate in HUS and in HAS. The presence of species-specific substances in mammalian follicular fluid is discussed.