An assessment of new sperm tests for male infertility

Lack of trusted diagnostic tools for undetermined male infertility

Semen analysis is the cornerstone of evaluating male infertility, but it is imperfect and insufficient to diagnose male infertility. As a result, about 20% of infertile males have undetermined infertility, a term encompassing male infertility with an unknown underlying cause. Undetermined male infertility includes two categories: (i) idiopathic male infertility-infertile males with abnormal semen analyses with an unknown cause for that abnormality and (ii) unexplained male infertility-males with "normal" semen analyses who are unable to impregnate due to unknown causes. The treatment of males with undetermined infertility is limited due to a lack of understanding the frequency of general sperm defects (e.g., number, motility, shape, viability). Furthermore, there is a lack of trusted, quantitative, and predictive diagnostic tests that look inside the sperm to quantify defects such as DNA damage, RNA abnormalities, centriole dysfunction, or reactive oxygen species to discover the underlying cause. To better treat undetermined male infertility, further research is needed on the frequency of sperm defects and reliable diagnostic tools that assess intracellular sperm components must be developed. The purpose of this review is to uniquely create a paradigm of thought regarding categories of male infertility based on intracellular and extracellular features of semen and sperm, explore the prevalence of the various categories of male factor infertility, call attention to the lack of standardization and universal application of advanced sperm testing techniques beyond semen analysis, and clarify the limitations of standard semen analysis. We also call attention to the variability in definitions and consider the benefits towards undetermined male infertility if these gaps in research are filled.

Does methylphenidate use affect sperm parameters in patients undergoing infertility investigation? A retrospective analysis of 9769 semen samples

OBJECTIVES

Methylphenidate (MPH) is the most widely prescribed therapy for attention deficit hyperactivity disorder. Animal studies have shown a potential adverse effect of MPH exposure on male fertility. We examined the impact of MPH on human male sperm parameters.

DESIGN

Sperm parameters of 9769 samples from patients 18 years of age or older, collected as part of the basic evaluation of couples referred to the Infertility Clinic were analyzed retrospectively. We divided the study population into three groups according to MPH purchasing information: MPH purchased ≤ 90 days prior to sperm analysis-current users (n = 83), MPH purchased > 90 days prior to sperm analysis-past users (n = 293), and MPH-naïve patients (n = 9393).

METHODS

All sperm samples were analyzed by the same laboratory technician team for the following routine parameters: semen volume, sperm concentration, percentage of motile sperm, and percentage of normal morphology according to World Health Organization. The analysis of the samples was completed by evaluation of total sperm count, total sperm motility, and percentage of fast and slow motile cells. Sperm morphology was evaluated by a laboratory technician using methodological examination according to the strict Kruger-Tygerberg criteria.

RESULTS

Methylphenidate exposure did not affect sperm morphology but was associated with increased sperm concentration as well as increased total sperm count and total sperm motility among current and past users compared with MPH-naïve patients. In particular, progressive motility and total motile sperm count were significantly increased following MPH use. A multivariate analysis adjusting for age and current smoking was conducted, further supporting a positive correlation between current MPH use and increased values of total sperm count and total sperm motility.

LIMITATIONS

Our study has several inherent weaknesses, foremost of which is its retrospective nature. Another notable weakness is that medication purchasing data may not accurately reflect MPH exposure in the study population. Patients may be purchasing MPH and not taking it as prescribed.

CONCLUSIONS

In the present study, we could not demonstrate a negative impact of methylphenidate treatment on sperm parameters in adults with ADHD. Hence, we may assume that methylphenidate does not negatively affect male fertility.

Altered microRNAs expression levels of sperm and seminal plasma in patients with infertile ejaculates compared with normozoospermic males

Approximately 15% of couples are unable to conceive after one year of unprotected intercourse. Because sperm can be accessed with ease, it is reasonable to search for non-invasive biomarkers in semen. MicroRNAs are a family of short single-stranded non-coding RNA molecules that are capable of regulating gene expression and causing mRNA degradation. We studied the most common 11 spermatogenesis-related microRNAs expression levels in sperm and seminal plasma from patients with oligozoospermic or asthenozoospermic ejaculates, and in men with normozoospermic ejaculates. Five of these miRNAs were significantly upregulated and three were downregulated in infertile males compared to men with normozoospermic ejaculates. A statistically significant negative correlation was found between the sperm concentration and several microRNA expression level (let-7a, miR-7-1-3p, miR-141, miR-200a, and miR-429, p < 0.0001) both in sperm and in seminal plasma. We also found positive correlation between sperm concentration and some miRNA expression levels (miR-15b, miR-34b, and miR-122, p < 0.001) in sperm and in seminal plasma. This is the first study to demonstrate differences between sperm and seminal plasma miRNA expression level and to identify a correlation between the sperm concentration and miRNAs expression level. Therefore, these MiRNAs could have the potential be used as non-invasive biomarkers to diagnose males with impaired sperm production.

Characterization of fertility associated sperm proteins in Aseel and Rhode Island Red chicken breeds

This study focused on characterization of fertility associated proteins in Aseel and RIR roosters and was conducted on two generations of birds. Roosters were divided into high (>50%) and low fertility groups (<50%) based on sperm function tests and fertility rate in both the generations. Polyclonal antibodies were raised in rabbits against sperm proteins of first generation highly fertile roosters and tested for characterization of fertility associated sperm proteins in the second generation of same roosters. IgG-fraction against proteins (Anti-SP-IgG) was reacted with sperm proteins of both high and low fertile roosters of second generation on immunoblots. Sperm proteins present in highly fertile roosters were further characterized by Mass Spectrometry (MS). Use of SDS-PAGE for evaluation of sperm extracts of Aseel and RIR breeds resulted in resolution of 16 and 10 proteins on 12% acrylamide gels. Anti-SP-IgG reacted with eight and ten sperm proteins of Aseel and RIR roosters on immunoblots. The SDS-PAGE and immunoblotting analysis also indicated a variation in sperm proteins among two breeds and high/low fertile roosters. The MS analysis indicated matching of 20, 30, and 20, 25 kDa proteins (associated with high fertility rate) of Aseel and RIR roosters with immunoglobulin kappa chain variable, phospholipase A₂ (PLA2), hypothetical N332-08551 partial and cystatin like partial proteins with a top score of 41, 46, 52 and 43, respectively. Considering the function and importance of matching proteins in male reproduction, these proteins may be further explored as potential markers for fertility evaluation of Aseel and RIR roosters.

A systematic review and meta-analysis to determine the effect of sperm DNA damage on in vitro fertilization and intracytoplasmic sperm injection outcome

Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage (assessed by SCSA, TUNEL, SCD, or Comet assay) and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles (with a total of 56 studies) including 16 IVF studies, 24 ICSI studies, and 16 mixed (IVF + ICSI) studies. These studies measured DNA damage (by one of four assays: 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet) and included a total of 8068 treatment cycles (3734 IVF, 2282 ICSI, and 2052 mixed IVF + ICSI). The combined OR of 1.68 (95% CI: 1.49–1.89; P < 0.0001) indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF (16 estimates, OR = 1.65; 95% CI: 1.34–2.04; P < 0.0001), ICSI (24 estimates, OR = 1.31; 95% CI: 1.08–1.59; P = 0.0068), and mixed IVF + ICSI studies (16 estimates, OR = 2.37; 95% CI: 1.89–2.97; P < 0.0001) were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.

Systematic characterization of seminal plasma piRNAs as molecular biomarkers for male infertility

Although piwi-interacting RNAs (piRNAs) play pivotal roles in spermatogenesis, little is known about piRNAs in the seminal plasma of infertile males. In this study, we systematically investigated the profiles of seminal plasma piRNAs in infertile males to identify piRNAs that are altered during infertility and evaluate their diagnostic value. Seminal plasma samples were obtained from 211 infertile patients (asthenozoospermia and azoospermia) and 91 fertile controls. High-throughput sequencing technology was employed to screen piRNA profiles in seminal plasma samples pooled from healthy controls and infertile patients. The results identified 61 markedly altered piRNAs in infertile patient groups compared with control group. Next, a quantitative RT-PCR assay was conducted in the training and validation sets to measure and confirm the concentrations of altered piRNAs. The results identified a panel of 5 piRNAs that were significantly decreased in seminal plasma of infertile patients compared with healthy controls. ROC curve analysis and risk score analysis revealed that the diagnostic potential of these 5 piRNAs to distinguish asthenozoospermic and azoospermic individuals from healthy controls was high. In summary, this study identifies a panel of piRNAs that can accurately distinguish fertile from infertile males. This finding may provide pathophysiological clues about the development of infertility.

Panel of five microRNAs as potential biomarkers for the diagnosis and assessment of male infertility

OBJECTIVE

To validate a set of five microRNAs (miRNAs) as specific biomarkers for the assessment of male infertility.

DESIGN

Quantitative real-time polymerase chain reaction (qRT-PCR) validation study.

SETTING

University research and clinical institutes.

PATIENT(S)

Two hundred twenty-six men presenting at an infertility clinic.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Validation analysis of a set of miRNAs in human purified spermatozoa and testicular biopsies.

RESULT(S)

Five miRNAs (hsa-miR-34b*, hsa-miR-34b, hsa-miR-34c-5p, hsa-miR-429, and hsa-miR-122) were confirmed with the use of qRT-PCR analysis in validation sets in patients with different forms of spermatogenic impairments (subfertile and nonobstructive azoospermia [NOA]) and control subjects. We found that hsa-miR-429 was significantly increased and the four other miRNAs were decreased in both tested groups compared with normal control subjects. Computing the area under the receiver operating characteristic curve (AUC) value for each of the five miRNAs, we showed that they separated the tested groups with high accuracy (range 0.777-0.988), except for hsa-miR-429 (AUC 0.475), in patient samples with NOA. Furthermore, with the use of support vector machine classification combining these five miRNAs, we found that they discriminated individuals with, respectively, subfertility and NOA from control subjects with an accuracy of 98.65% and 99.91%, a specificity of 98.44% and 99.69%, and a sensitivity of 98.83% and 100%.

CONCLUSION(S)

Our finding suggests that these five miRNAs have potential as novel noninvasive biomarkers to diagnose patients with subfertility. Except for hsa-miR-429, the combination of these miRNAs with other conventional tests would improve the diagnostic accuracy for detecting patients with different forms of NOA.

Assessing the reproductive health of men with occupational exposures

The earliest report linking environmental (occupational) exposure to adverse human male reproductive effects dates back to1775 when an English physician, Percival Pott, reported a high incidence of scrotal cancer in chimney sweeps. This observation led to safety regulations in the form of bathing requirements for these workers. The fact that male-mediated reproductive harm in humans may be a result of toxicant exposures did not become firmly established until relatively recently, when Lancranjan studied lead-exposed workers in Romania in 1975, and later in 1977, when Whorton examined the effects of dibromochloropropane (DBCP) on male workers in California. Since these discoveries, several additional human reproductive toxicants have been identified through the convergence of laboratory and observational findings. Many research gaps remain, as the pool of potential human exposures with undetermined effects on male reproduction is vast. This review provides an overview of methods used to study the effects of exposures on male reproduction and their reproductive health, with a primary emphasis on the implementation and interpretation of human studies. Emphasis will be on occupational exposures, although much of the information is also useful in assessing environmental studies, occupational exposures are usually much higher and better defined.

Sperm retrieval techniques

Since the advent of intracytoplasmic sperm injection in 1992, sperm retrieval procedures have been routinely employed to treat male infertility owing to azoospermia. With obstructive azoospermia, sperm is potentially harvestable from the vas deferens, epididymis, and testicle using percutaneous and open sperm retrieval procedures that are relatively straightforward and reliable. In nonobstructive azoospermia, sperm is generally found only in the testicles and can often be difficult to retrieve. Several approaches aimed at maximizing sperm yield in this condition have been developed, but only 50% of men with nonobstructive azoospermia will have clinically usable sperm. Multibiopsy testicular sperm extraction (TESE), microdissection TESE, and fine-needle-aspiration map-guided TESE are three common methods currently employed to locate and retrieve sperm in these difficult cases. Other factors that influence the use of surgically retrieved sperm for assisted reproduction include differences in sperm DNA integrity, the expertise of the surgeon and the andrology laboratory, and the described differences in the viability of sperm from different anatomical sources after freezing and thawing.

Evaluating a novel panel of sperm function tests for utility in predicting intracytoplasmic sperm injection (ICSI) outcome

PURPOSE

The objective of this study was to evaluate a panel of three sperm function tests; tests known to assess different aspects of sperm functionality and genomic integrity, the: 1) Sperm DNA Accelerated Decondensation (SDAD(TM)) Test, 2) Sperm DNA Decondensation (SDD(TM)) Test, and 3) Sperm Penetration Assay (SPA), determining if positive and negative test scores correlated with failed and successful ICSI outcomes, respectfully.

METHODS

A prospective, double blinded, cohort study was performed. One study sample (ejaculated semen) was collected by each of the 60 male partners of the 60 couples enrolled in the study; males whose female partners were found to have no major female factor issues. The sperm from each male was analyzed in the SPA, and SDAD and SDD Tests, and used for ICSI (1 ICSI cycle per couple).

RESULTS

The ICSI cycle pregnancy rate for this study was 50 %, with a delivery rate=40 % (n=60 ICSI cycles). The SPA and SDD Test scores did not significantly predict ICSI outcome when used as stand-alone tests (p>>0.05). However, when the SPA and SDD Test scores were used together, ICSI outcomes for a subgroup of 10 (16.7 %) males, were significantly predicted (p=0.03), with 1 live birth, and 9 negatives where the transferred embryos did not implant. In total, 38.4 % of the couples in this study were found to have a very poor chance for a successful ICSI cycle.

CONCLUSION

SDAD Test scores alone, and SPA and SDD Test scores used together, significantly predicted failed ICSI outcomes. This indicates that the scores obtained when analyzing patients' sperm using a panel of sperm function tests; specifically, the SPA, and SDAD and SDD Tests, can be used to identify infertile couples who should not be directed to ICSI.

Altered Profile of Seminal Plasma MicroRNAs in the Molecular Diagnosis of Male Infertility

BACKGROUND

Although microRNAs (miRNAs) play essential roles in spermatogenesis, little is known about seminal plasma miRNAs in infertile men. We investigated the profile of seminal plasma miRNAs in infertile men to identify miRNAs that are altered in infertility; we then evaluated their diagnostic value.

METHODS

Seminal plasma samples were obtained from 289 infertile men and 168 age-matched fertile control individuals. The stability of the miRNAs was first assessed by time-course and freeze–thaw cycle analyses. The Solexa sequencing technology was used for an initial screen of the miRNAs in samples pooled from 45 patients with nonobstructive azoospermia, 58 patients with asthenozoospermia, and 100 fertile controls. A stem–loop quantitative reverse-transcription PCR (RT-qPCR) assay was conducted in the training and verification sets to confirm the concentrations of the altered miRNAs in 73 patients with nonobstructive azoospermia, 79 patients with asthenozoospermia, 34 patients with oligospermia, and 68 fertile controls.

RESULTS

The miRNAs in seminal plasma were stable. The Solexa sequencing analysis demonstrated 19 markedly altered miRNAs in the patient groups, compared with the control group. RT-qPCR analysis identified 7 miRNAs (miR-34c-5p, miR-122, miR-146b-5p, miR-181a, miR-374b, miR-509–5p, and miR-513a-5p) as markedly decreased in azoospermia but increased in asthenozoospermia. The area under the ROC curve for these miRNAs ranged from 0.733 to 0.921, markedly higher than for routine biochemical parameters (0.510–0.622). Moreover, the concentrations of some selected miRNAs were also increased in the semen sperm of the asthenozoospermia patients.

CONCLUSIONS

The measurement of miRNAs in seminal plasma provides a novel, noninvasive approach for diagnosing male infertility.