Evaluation of reference values of standard semen parameters in fertile Egyptian men

The future of sperm: a biovariability framework for understanding global sperm count trends

The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from 'Western' countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists' public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.

Geographic variation in semen parameters from data used for the World Health Organization semen analysis reference ranges

OBJECTIVE

To study geographic variations in sperm parameters using data from the trials that defined the reference ranges of the World Health Organization 2021 manual.

DESIGN

Retrospective evaluation of the data used to define the World Health Organization reference ranges.

SETTING

Not applicable.

PATIENT(S)

Data from 11 studies, including 3,484 participants across 5 continents.

INTERVENTION(S)

The data were divided according to geographic locations.

MAIN OUTCOME MEASURE(S)

Differences in sperm parameters.

RESULT(S)

The semen volume was significantly lower in samples from Asia and Africa than in other regions. The sperm concentration was the lowest in Africa and highest in Australia. The total motile sperm count (TMSC) and total motile progressive sperm count (TMPS) were significantly lower in Africa than in other regions. The TMSC and TMPS in Asia and the United States were significantly lower than in Europe and Australia. The 5th percentile of the sperm concentration was lowest in the United States (12.5 × 10⁶/mL). The 5th percentile for the normal sperm morphology was lowest in the United States (3%) and highest in Asia (5%). The 5th percentile for the TMSC and TMPS were lowest in Africa (TMSC, 15.08 million; TMPS, 12.06 million) and the United States (TMSC, 18.05 million; TMPS, 16.86 million) and highest in Australia (TMSC, 29.61 million; TMPS, 25.80 million).

CONCLUSION(S)

Significant geographic differences in sperm parameters exist, and regional fertility societies should consider adding their own reference ranges on the basis of local experience and treatment outcomes.

Spatiotemporal trends in human semen quality

Over the past four decades, studies of various designs have reported spatial and temporal trends in human semen quality. Several standardized-methodology studies in homogeneous populations that compare specific cities within a country or a continent provide clear evidence of geographical differences in sperm production, even over short distances within the same country. Human sperm production is widely believed to be declining over time, but evidence from the scientific literature is less clear. Studies based on repeated cross-sectional data from a single centre have shown mixed results. Among the numerous retrospective studies conducted in a single centre, only some included homogeneous groups of men and appropriate methods, and most of them suggest a temporal decrease in human sperm production in the geographical areas considered. Conclusions reporting temporal trends in sperm production that came from existing retrospective multicentre studies based on individual semen data and those using means, medians or estimates of sperm production are questionable, owing to intrinsic limitations in the studies performed. Regardless of study design, studies on the percentage of motile or morphologically normal spermatozoa are still limited by the inherent variability in assessment. Overall, available data do not enable us to conclude that human semen quality is deteriorating worldwide or in the Western world, but that a trend is observed in some specific areas. To understand these trends and contrasts in sperm and semen quality, prospective studies should be encouraged and combined with assessment of the male exposome.

Several studies over the past few decades have suggested that sperm quality varies by geographical region and might be subject to a temporal decline worldwide. However, the data supporting these conclusions have come from studies of various methodologies and heterogeneous populations, making them unreliable. In this in-depth Review, Chevrier and colleagues discuss the data surrounding discussion of spatiotemporal trends in semen parameters and consider how these trends and the factors promoting them interact.

The vast literature on human semen quality trends is extremely heterogeneous in terms of the populations studied and study designs, and so these studies have been unable to draw firm conclusions.

Understanding the data around spatiotemporal semen trends requires a focus on the methodological choices and application of criteria to filter findings from the studies with optimal design.

Numerous appropriately designed studies suggest unambiguous geographical contrasts in human sperm production; however, evidence of a decline in sperm production is reliable only in specific populations and cities in which studies with a complete set of quality criteria have been conducted.

By contrast, suggestions of a worldwide drop in human semen quality on the basis of retrospective multicentre studies cannot be substantiated, owing to intrinsic limitations in the studies performed.

Many and varied factors of variation, in particular the diverse modalities of assessment, do not enable us to conclude that clear temporal trends of sperm motility and normal morphology are present.

Progress in our understanding of the highlighted trends and their causal factors requires prospective studies that minimize all known biases combined with the assessment of men’s exposome.

The statistical foundation of the reference population for semen analysis included in the sixth edition of the WHO manual: a critical reappraisal of the evidence

In the most recent version of the ‘WHO Laboratory Manual For The Examination And Processing Of Human Semen’, the updated target population used to infer reference values included 3589 fertile subjects, representative of 12 countries and 5 continents, and 10 studies. We have critically evaluated the newly proposed distribution of semen examination results using an approach borrowed from clinical chemistry laboratories and based on the recommendations of the International Federation of Clinical Chemistry for estimation of reference intervals. Surprisingly, most prerequisites to produce common reference intervals through multicentric data were not met. Moreover, when we assessed with the bootstrap method the descriptive reference values obtained from raw data of the 10 individual studies for sperm concentration, sperm number, motility and normal forms, we found that none of the populations was completely correctly described by the reference centiles. We concluded that aggregated data used to build the reference distribution cannot be considered to originate from the same population, and this can result from real differences among individuals or different methodological approaches used in the various studies. Transferability conditions across studies did not seem to have been met. Our findings strengthen the relevance of concerns regarding the use of reference populations in the World Health Organization manual to discriminate between fertile and infertile men.

An evaluation of changes over time in the semen parameters data used for the World Health Organization semen analysis reference ranges

BACKGROUND

Previous meta-analyses concluded that there is a decline in sperm parameters over time. This conclusion might be incorrect due to inherent biases or focusing only on a single parameter - sperm concentration.

OBJECTIVE

To study trends in sperm parameters over the past twenty years using data from the trials that defined the reference ranges of the World Health Organization manual.

MATERIALS AND METHODS

Retrospective evaluation of the data used to define the World Health Organization reference ranges. The data from 11 studies, including 3589 participants between 1996-2016, were divided into three period groups based on the decade of study. Differences in semen parameters' distribution were presented in boxplot. P-values were calculated by the Kruskal Wallis rank-sum test followed by Dunn post-hoc test. Analyses were conducted using the R programming language.

RESULTS

A small decrease was noted in mean sperm concentrations (88.1 million/ml, 87.6 million/ml and 77.2 million/ml for the first second and third decades respectively) (p<0.01). However, the 5^th percentile of sperm concentration for the third decade was higher than the first or second decades (18 million/ml vs. 14.9 million/ml and 15 million/ml respectively). No significant differences were noted in progressive motility over the years (p = 0.32). The percent of morphologically normal sperm decreased between the first (24.2%) and the second (12.6%) periods of the study (p<0.001) and then increased in the third decade (14.2%) (p<0.01). While TMC declined between the second and third decades (189 million and 153.9 million respectively, p<0.001), at levels unlikely to decrease fertility. However, the 5^th percentile of the TMC remained stable at 24.9, 20.8 and 20.6 million, for the first, second and third decades respectively (p = 0.36).

DISCUSSION AND CONCLUSION AND RELEVANCE

Trends in sperm parameters over the last three decades do not seem to be clinically significant. This article is protected by copyright. All rights reserved.

Identification and Structure Prediction of Human Septin-4 as a Biomarker for Diagnosis of Asthenozoospermic Infertile Patients-Critical Finding Toward Personalized Medicine

Semen parameters are been found as a key factor to evaluate the count and morphology in the given semen sample. The deep knowledge of male infertility will unravel with semen parameters correlated with molecular and biochemical parameters. The current research study is to identify the motility associated protein and its structure through the in-silico approach. Semen samples were collected and initial analysis including semen parameters was analyzed by using the World Health Organization protocol. Semen biochemical parameters, namely, seminal plasma protein concentration, fructose content, and glucosidase content were calculated and evaluated for correlation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) were carried out for identification of Septin-4 presence in the semen sample. Mascot search was done for protein conformation and in-silico characterization of Septin-4 by structural modeling in Iterative Threading Assembly Refinement (I-TASSER). Twenty-five nanoseconds molecular dynamics (MD) simulations results showed the stable nature of Septin-4 in the dynamic system. Overall, our results showed the presence of motility-associated protein in normospermia and control samples and not in the case of asthenospermia and oligoasthenospermia. Molecular techniques characterized the presence of Septin-4 and as a novel biomarker for infertility diagnosis.

Distribution of semen examination results 2020 - A follow up of data collated for the WHO semen analysis manual 2010

BACKGROUND

It is now 11 years since publication of the WHO 2010 guidelines for semen assessment values, and it is critical to determine whether they are still valid and/or whether they should be modified.

OBJECTIVES

To utilise data published since 2010 and combine these with data used in the 2010 assessment to provide an updated and more comprehensive representation of the fertile man. This may be utilised to present an updated distribution of values for use by WHO in 2021.

MATERIALS AND METHODS

Two specific analyses were performed namely, (1) Analysis 1: Examination of published data following publication of WHO 2010 [termed 2010-2020 data]. (2) Analysis 2: Examination of the data used to help formulate the 2010 distribution of values combined with the data from Analysis (1) [termed WHO 2020].

RESULTS

In total, data from more than 3500 subjects, from twelve countries and five continents were analysed. The 5^th centile values for concentration, motility and morphology are: 16 × 10⁶ /ml, 30% progressive motility [42% total motility] and 4% normal forms.

DISCUSSION

This study presents substantial additional information to establish more comprehensive and globally applicable lower reference values for semen parameters for fertile men although they do not represent distinct limits between fertile and subfertile men. There are still data missing from many countries and, some geographical regions are not represented. Moreover, the number of subjects although significant is still relatively low (<4000).

CONCLUSION

These distributions of values now include semen analysis providing a more global representation of the fertile man. Increasing the number of subjects provides robust information that is also more geographically representative.

Home sperm testing device versus laboratory sperm quality analyzer: comparison of motile sperm concentration

OBJECTIVE

To test the ability of the smartphone-based YO Home Sperm Test to accurately and precisely measure motile sperm concentration (MSC) versus the SQA-Vision, an automated laboratory semen analyzer.

DESIGN

MSC compared for the YO device on Galaxy and iPhone smartphones versus the SQA-Vision in a double-blind manner.

SETTING

Academic medical center.

PATIENT(S)

Donor semen samples from 24 men in 144 aliquots.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Accuracy, precision, and agreement assessed between the YO device and the SQA-Vision for MSC results.

RESULT(S)

The YO device demonstrated good correlation and good to moderate agreement with the SQA-Vision for MSC results up to a range of 94 × 10⁶/mL with Pearson and concordance correlation coefficient above 0.92. The YO also showed a very high level of accuracy (97.8%) with positive and negative percent agreement above 94%. The difference in coefficient of variation between the YO and the SQA-Vision was low (between 9.4% and 11.2%) and not statistically significant. The precision among the YO phone devices was lower (16.0%) than the manufacturer's claim of ≤20%.

CONCLUSION(S)

The smartphone-based device has a high level of accuracy and precision when compared with the SQA-Vision. It can detect samples with abnormally "low" MSC (below 6 × 10⁶/mL cutoff), which supports its use as an effective home sperm test for screening "low" and "moderate/normal" MSC cases. In addition, the device effectively identifies varying levels of normal MSC in a precise manner over a wide range of normal MSC. Thus, the YO Score can improve patient satisfaction and empowerment.