Validation of SwimCount™, a Novel Home-Based Device That Detects Progressively Motile Spermatozoa: Correlation with World Health Organization 5th Semen Analysis

Contraceptive efficacy: Determining the threshold for effective suppression based on sperm concentration, motility, and morphology

INTRODCTION

Human spermatogenesis is a complex process that transforms spermatogonial stem cells through mitosis and meiosis to spermatozoa. Testosterone is the key regulator of the terminal stages of meiosis, adherence of spermatids to Sertoli cells, and spermiation. Follicle-stimulating hormone (FSH) may be required for early spermatogenesis and is important for maintaining normal spermatogenesis in men. Hormonal contraception suppresses FSH, luteinizing hormone, and intratesticular testosterone concentration, resulting in marked suppression of sperm output.

RESULTS

Clinical trials using testosterone alone or testosterone plus progestin demonstrate that sustained suppression of sperm concentration to ≤1 million/mL is sufficient to prevent pregnancy in the female partner. New agents that target spermatogenesis could use this as a target for contraceptive efficacy while others that block sperm function or transport may require a lower threshold. When sperm concentrations are suppressed to such low levels, measurement of sperm motility and morphology is technically difficult and unnecessary. With current data from fertile and infertile men, it is not possible to establish a lower limit of sperm motility or percent normal morphology that equates to the prevention of conception. New compounds that decrease sperm motility or alter sperm morphology may need to demonstrate a complete absence of sperm motility or altered morphology in all spermatozoa in the ejaculate. Sperm function tests may be useful depending on the mechanism of action of each new compound.

CONCLUSION

Monitoring of sperm surrogate markers to ensure effective contraception relies on laboratories experienced in semen analyses. The development of at-home tests to assess sperm parameters has progressed rapidly. Some tests have been assessed in clinical trials and approved by regulatory agencies for at-home use for fertility assessment. However, caution must be exercised in using these tests as many have not been rigorously validated against semen parameters measured in laboratories by trained technologists using standardized tests defined in the World Health Organization Semen Manual.

Evolution of the basic semen analysis and processing sperm

PURPOSE OF REVIEW

The sixth edition of the World Health Organization (WHO) laboratory manual for the examination and processing of human semen was recently published with specific step-by-step instructions for semen evaluation and sperm processing. Point-of-care (POC) testing for semen evaluation and microfluidics for sperm processing are rapidly evolving technologies that could impact how we evaluate and process sperm. Understanding the updated manual in the context of these novel technologies is important.

RECENT FINDINGS

Proper standardization of semen evaluation and sperm processing will allow for consistent high-quality results among laboratories worldwide. POC testing could improve access to semen evaluations that generate referrals to male infertility specialists for further assessment. Microfluidics can select functional sperm with decreased DNA fragmentation in semen and testicular biopsy samples for assisted reproductive technology (ART). Clinical outcomes, such as pregnancy rates and live birth rates, have not been shown to be consistently improved with these technologies compared to conventional techniques, although high level evidence research in this area is limited.

SUMMARY

POC testing and microfluidics have the potential to be combined with machine learning technologies to improve fertility care. If these technologies are appropriately optimized, they could change how we evaluate and process sperm, and potentially lead to improved ART outcomes.

New Approaches to Define The Functional Competency of Human Sperm Subpopulations and Its Relationship to Semen Quality

BACKGROUND

This study aimed at comparing a comprehensive set of functional and structural sperm characteristics between sperm motility fractions and correlating results to the standard semen parameters. By grouping related variables, our objective was to establish the predictive power of semen parameters and whether they accurately reflect the functionality of sperm motility fractions or merely a small set of parameters within individual fractions.<br />Materials and Methods: In this non-invasive experimental study, donor semen samples (n=55) were separated via<br />double density gradient centrifugation, isolating a high (HM) and low motile (LM) sperm fraction. Fractions were evaluated for percentage vitality, chromatin integrity, mature spermatozoa, motility and kinematic parameters, hyperactivation, positive reactive oxygen species, intact mitochondrial membrane potential (MMP) and acrosome reaction.<br />Results: HM fractions had significantly (P<0.001) enhanced percentages of induced acrosome reaction (HM, 55.6 ±<br />14.3%, LM, 25.0 ± 16.5%), motility and kinematic parameters, hyperactivation, vitality (HM, 70.4 ± 9.7%, LM, 47.9<br />± 10.3%), mitochondrial membrane intactness (HM, 67.2 ± 10.4%, LM, 44.7 ± 15.0%) and mature spermatozoa (HM,<br />83.4 ± 10.0%, LM, 64.6 ± 8.2%) with intact chromatin (HM, 80.5 ± 8.1%, LM, 71.3 ± 8.0%). Various sperm morphology abnormalities correlated with LM fractions' grouped motility parameters (range, 0.46 to 0.51; range -0.4 to<br />-0.75), whereas combined semen traits of total motility, progressive motility, viscosity and mucus penetration (MPT) correlated with HM fractions' grouped motility parameters (range, 0.44 to 0.84).

CONCLUSION

Collectively, total and progressive motility, viscosity and MPT may represent a reliable grouping of semen parameters for predicting the quality of HM sperm fractions. Separating the same donor semen samples into two significantly diverse motility sperm fractions could be a potential model in mimicking the qualities of fertile and sub-fertile males' sperm populations and used for future research on the improvement of sperm subpopulations from males with different fertility statuses.

Clinical Update on Home Testing for Male Fertility

Male factor infertility accounts for about 50% of the incidence of infertility in couples. In current practice, the men must attend a clinic or hospital facility to provide a semen analysis, which is key to the diagnosis of the male reproductive potential. However, many men are often embarrassed with the process and conventional semen analysis requires complex, labor intensive inspection with a microscope. To mitigate these problems, one of the solutions can be at-home semen analysis. In this review we examine the literature of currently available at home semen analysis test kits, describe their limitations, and compare them to the conventional lab-based methods.

Land use and semen quality: A fertility center cohort study

This study explored the association between built environment and semen parameters among men who sought fertility evaluation. We used a data of 5,886 men living in the Seoul capital area whose semen was tested at a single fertility center during 2016–2018. Distance to fresh water, the coast, major roadways, and neighborhood greenness measured by Normalized Difference Vegetation Index (NDVI) were evaluated. Outcome indicators were semen volume, sperm concentration, percentage of progressive motility, vitality, normal morphology, and total motile sperm count. Linear regression models were fitted to standardized values of six semen indicators. Majority of men were white-collar, clerical, and service workers. Linear associations between built environment features and semen quality indicators were not evident except for NDVI within 500 m and sperm vitality (β = 0.05; 95% confidence interval (CI): 0.01, 0.09). The 2^nd quartile of distance to fresh water was associated with lower progressive motility compared to the 1^st quartile (β = −0.10; 95% CI: −0.17, −0.03). Proportion of vitality was higher among men in the 2^nd quartile of distance to roadways than those in the 1^st quartile (0.08; 95% CI: 0.01, 0.15). Men in the 2^nd quartile of NDVI had higher total motile sperm count (0.09; 95% CI: 0.01, 0.17). In the multi-exposure model, the positive association between NDVI and vitality remained (0.03; 95% CI: 0.00, 0.06). We observed potential evidence regarding the impact of built environment on male fertility, specifically a positive association between residential greenness and sperm vitality among men with a history of infertility.

Simplified sperm testing devices: a possible tool to overcome lack of accessibility and inconsistency in male factor infertility diagnosis. An opportunity for low- and middle- income countries

Background

Manual semen assessment (MSA) is a key component in a male’s fertility assessment. Clinicians rely on it to make diagnostic and treatment decisions. When performed manually, this routine laboratory test is prone to variability due to human intervention which can lead to misdiagnosis and consequently over- or under- treatment. For standardisation, continuous training, quality control (QC) programs and pricy Computer-Assisted Sperm Analysis (CASA) systems have been proposed, yet, without resolving intra- and inter-laboratory variability. In response, promising simplified sperm testing devices, able to provide cost-effective point-of-care male infertility diagnosis are prospected as a plausible solution to resolve variability and increase access to sperm testing.

Materials and methods

A throughout literature research for semen testing, sperm analysis, smart-phone assisted semen analysis, ‘at-home’ semen testing, male infertility, infertility in developing countries, infertility in low- and middle-income countries (LMIC) and quantitative sperm analysis was performed. A total of 14 articles, specific to ‘at-home’ simplified sperm assessment, were included to treat the core subject.

Results

Continuous training and consistent QC, are sine qua none conditions to achieve accurate and comparable MSA. Compliance does not rule-out variability, nevertheless. Emerging simplified sperm assessment devices are an actual alternative to resolve the lack of standardisation and accessibility to sperm analysis. YO ® , SEEM ® , and ExSeed ® are commercially available, user-friendly smartphone-based devices which can accurately measure volume, sperm concentration (millions/ml) and total motile sperm count. More broadly, by cost-effectiveness, availability, accuracy and convenient application, these devices could effectively select patients for first-line artificial reproduction treatments such as intrauterine insemination.

Conclusions

Accuracy and cost-effectiveness make smart-phone based sperm testing devices a practical and realistic solution to overcome variability in MSA. Importantly, these tools represent an actual opportunity to standardise and improve male subfertility diagnosis and treatment, especially in LMIC. However, before clinical application is possible, guidelines, further testing with special attention on accuracy in washed sperm, availability, cost-benefit and reliability are required.

Point-of-care semen analysis of patients with infertility via smartphone and colorimetric paper-based diagnostic device

Male infertility affects millions of males worldwide and is rising in prevalence due to social and environmental conditions. However, men often feel too embarrassed to receive a semen analysis in the hospital due to social stigmas. To overcome this problem, we developed a 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide test strip to distinguish semen samples with low total motile sperm concentration from those with normal motile sperm concentration. This is a point-of-care colorimetric semen analytical method with a one-step, inexpensive, equipment-free evaluation process, and adequate accuracy validated in a 42-sample clinical trial. In this study, results were evaluated visually and with a smartphone application. Using visual observation methods, the area under the curve (AUC) was 0.71 (95% of confidence interval = 0.55-0.86; p = 0.021), sensitivity was 41%, specificity was 95%, positive predictive value was 90%, negative predictive value (NPV) was 59.4%, and accuracy was 67%. Using a smartphone recording and analytical system, AUC was 0.766 (95% of confidence interval = 0.612-0.92; p = 0.003), sensitivity was 96%, specificity was 65%, PPV was 75%, NPV was 92.9%, and accuracy was 80.9%. This work demonstrated a screening tool that could elevate semen analysis to the level of routine healthcare and provide for private, in-home self-assessment.

Bioinformatic prediction of the structure and characteristics of human sperm acrosome membrane-associated protein 1 (hSAMP32) and evaluation of its antifertility function in vivo

Human sperm acrosome membrane-associated protein 1 (hSAMP32) plays an important role in the acrosome reaction, sperm-egg primary binding, secondary binding and fusion processes. However, its spatial structural and invivo antifertility function remain unknown. In this study, we first analysed the physical and chemical characteristics and antigenic epitopes of immunised mice using bioinformatics. Then, we constructed the prokaryotic expression vector pcDNA3.1-hSAMP32 to immunise BALB/c mice invivo. IgG antibodies in the serum were detected, and the litter size of female mice and the number of the hamster eggs penetrated were counted. hSAMP32 was found to contain six hydrophilic regions and a signal peptide beginning at amino acid position 29. The transmembrane region of hSAMP32 was located within amino acids 217-239 with α-helices and random coil structures. We predicted five antigenic epitopes. The molecular weight of hSAMP32 was 59 kDa. Moreover, the results of invivo studies revealed that 56 days after the first immunisation, the litter size was significantly smaller for female pcDNA-3.1(+)-hSAMP32-immunised (mean±s.d. 4.33±1.21) than control mice (9.50±0.55), indicating that the immunocontraception vaccine had an antifertility effect. This experiment presents a theoretical and experimental basis for in-depth study of the hSAMP32 mechanism within the sperm-egg fusing process and for the screening of antigenic epitopes with immunocontraceptive properties.

Recent advances in clinical diagnosis and treatment of male factor infertility

Infertility is a significant global health issue affecting around 8-12% of couples worldwide with male factor infertility accounting for a substantial proportion of these cases. Despite significant advances within the past few decades, an etiology for male factor infertility cannot be identified in up to 80% of patients and thus, this continues to be an area of active study. This review aims to provide an update on recent advances in the field of male infertility including semen analysis and at-home semen testing, genetics, DNA fragmentation, surgical approaches, and the rise of telemedicine in the era of COVID19.