New generation of diagnostic tests for infertility: Review of specialized semen tests

Sperm aminopeptidase N identifies the potential for high-quality blastocysts and viable embryos in oocyte-donation cycles

STUDY QUESTION

Is there a relationship between human sperm aminopeptidase N (APN) and embryo development in humans?

SUMMARY ANSWER

Human sperm APN could possibly become a new molecular biomarker for identifying the potential for high-quality and usable embryos.

WHAT IS KNOWN ALREADY

The diagnosis of male fertility is one of the major concerns of reproductive medicine. Approximately 30-40% of men with otherwise normal fertility parameters are still unable to achieve pregnancy. The predictive clinical value of semen analysis to identify fertile or infertile males is limited; therefore, new diagnostic methodologies for sperm are urgently required. Sperm APN may be a relevant molecular marker due to its high concentration in sperm cells and its important roles in sperm physiology, such as its functions in motility, acrosome reaction and embryo development.

STUDY DESIGN, SIZE, DURATION

This study included 81 couples who underwent oocyte-donation cycles at Clínica IVI Bilbao (Spain), yielding 611 embryos, between September 2014 and July 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted in an assisted reproduction unit and an academic research laboratory. All the semen samples were examined and classified following World Health Organization guidelines. Spermatozoa were isolated from semen using the discontinuous colloidal silica gradient (45-90%) technique. Embryo quality and development were determined according to the Spanish Association of Reproduction Biology Studies (ASEBIR) criteria. Human sperm APN levels were analyzed by quantitative and semiquantitative flow cytometry.

MAIN RESULTS AND THE ROLE OF CHANCE

The most well-developed and usable blastocysts were associated with low sperm APN levels. Semen samples that had lower APN levels generated more expanded, hatched and usable blastocysts and fewer early, arrested and non-usable blastocysts. The cumulative probability of having well-developed blastocysts increased by 1.38-fold at Day 5 and 1.90-fold at Day 6 of embryo development, and the likelihood of having usable embryos increased by 1.48-fold, when semen samples with low APN levels were used during the ICSI technique.

LIMITATIONS, REASONS FOR CAUTION

The data were obtained from a single fertility clinic. A multicentre study will be required to confirm the results.

WIDER IMPLICATIONS OF THE FINDINGS

Human sperm APN has the potential to become a new molecular biomarker to help identify the potential for high-quality embryos and diagnose male infertility, especially when seminal parameters are close to the threshold values. It could be a crucial tool for couples for whom the number of usable blastocysts is critical for ART success.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Basque Government (GIC15/165) and the University of the Basque Country (UPV/EHU) (EHUA14/17). The authors declare that they have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Zearalenone interferes with the sperm-triggered inflammation in the bovine uterus in vitro: Negative impact on sperm motility and survival

Zearalenone (ZEN)-contaminated diets induce detrimental effects on the bovine reproduction. Recently, we reported that active sperm induce pro-inflammatory responses in bovine endometrial epithelial cells (BEECs) in vitro. This study aimed to investigate the impact of presence of ZEN on the sperm-uterine crosstalk in vitro. BEECs monolayers were stimulated by ZEN (10, 100, and 1000 ng/mL) for 0, 3, 6, 12, or 24 h and gene expressions were analyzed by real-time PCR. Moreover, BEECs were pre-exposed to ZEN (10, 100, and 1000 ng/mL) for 24 h then, co-incubated with sperm for 6 h. Conditioned media (CM) from a sperm-BEECs co-culture, after pre-exposure to ZEN, were harvested and exploited to challenge either polymorphonuclear cells (PMNs) or sperm. Both PMNs phagocytic activity toward sperm and sperm motility parameters were then assessed. Results showed that ZEN alone induced pro-inflammatory responses in BEECs through the induction of mRNA expressions of pro-inflammatory cytokines (TNFA and IL1B) and PGES1 at different time points. Pre-exposure of BEECs to ZEN, amplified the sperm-triggered upregulation of pro-inflammatory cytokines (TNFA and IL1B) and chemokine IL8 mRNA abundance in BEECs. Sperm-BEECs conditioned media, primed by ZEN, stimulated the PMNs phagocytosis for sperm whereas suppressed sperm motility parameters. Taken together, these findings indicate that the presence of ZEN augments the pro-inflammatory cascade triggered by sperm in BEECs, provokes PMNs phagocytosis for sperm, and reduces sperm motility parameters. Such immunological reactions may create a hostile environment for sperm competence and survival in the bovine uterus, thus impair fertility.

Correlation of sperm DNA damage with blastocyst formation: systematic review and meta-analysis

Background

The routine semen analysis fails to detect sperm DNA damage which contributes to the majority of male factor infertility. Sperm DNA fragmentation test (DFI) measures the sperm DNA damage. Blastocyst formation is an important step in IVF ± ICSI. At present, the literature lacks any data that correlates DFI and blastocyst formation.

Main body of the abstract

We searched MEDLINE and other databases till 2020 for the studies that reported on sperm DNA damage and blastocyst formation in assisted reproductive technology (ART). The outcomes analyzed were (1) a comparison of blastulation rates in high DFI and low DFI groups. (2) Comparison of blastulation rates in high DFI and low DFI groups based on (a) different sperm DNA fragmentation assays (COMET, SCD, SCSA, TUNEL), (b) different types of ART (IVF/IVF + ICSI/ICSI). 10 studies were included in this review. A non-significant increase in the blastocyst formation was observed in high DFI group (OR = 0.70; 95% CI = 0.4 to 1.21; P = 0.20) and with SCD and TUNEL assays.

Short conclusion

Our study emphasizes on sperm DNA fragmentation (sperm DNA damage) as an important marker of blastocyst formation. The results of this meta-analysis suggest that the high sperm DNA fragmentation may not adversely affect the blastocyst formation.

Sperm selection during ICSI treatments reduces single- but not double-strand DNA break values compared to the semen sample

PURPOSE

To detect a possible bias in sperm DNA fragmentation (SDF) testing when performed on semen samples or on those few spermatozoa selected for Intracytoplasmic Sperm Injection (ICSI) treatments.

METHODS

A multimethodological analysis of Single- and Double-Strand DNA Breaks (SSB and DSB, respectively) was performed through the Neutral Comet, the Alkaline Comet, the Sperm Chromatin Dispersion (SCD) and the Terminal deoxynucleotidyl transferase dUTP Nick End Labelling (TUNEL) assays. SDF was evaluated in (i) semen samples from 23 infertile patients (not achieving pregnancy or suffering recurrent miscarriage); (ii) samples after a Swim-up and (iii) spermatozoa microselected for ICSI (ICSI-S).

RESULTS

The analysis of 3217 ICSI-S revealed a significant reduction of SSB values compared to the Ejaculate and the Swim-up samples. On the contrary, DSB values were not reduced after any sperm selection method. The No-pregnancy group presented poorer semen parameters and higher SSB values. The Recurrent miscarriage group presented better semen parameters but also higher DSB values.

CONCLUSION

The analysis of SDF on semen samples may not be fully representative of those few spermatozoa selected for ICSI. Since oxidative stress impairs sperm motility and causes SSB, selecting a motile sperm may intrinsically imply choosing a sperm not affected by this damage. DSB have an enzymatic origin which does not affect motility, making it difficult to select a sperm without this damage. Therefore, ICSI treatments could be effective in patients presenting high SSB values. Patients presenting high DSB values should expect bad ICSI results if this damage is not reduced through other specific methods.

Regulation of Male Fertility by the Renin-Angiotensin System

The renin-angiotensin system (RAS) is a peptidic system known mainly for its roles in the maintenance of blood pressure and electrolyte and fluid homeostasis. However, several tissues and cells have been described to possess an intrinsic RAS that acts locally through different paracrine and autocrine mechanisms. In the male reproductive system, several components of this system have been observed in various organs and tissues, such as the testes, spermatozoa and seminal fluid. Some functions attributed to this local RAS are maintenance of seminal plasma electrolytes, regulation of steroidogenesis and spermatogenesis, and sperm functions. However, their specific actions in these locations are not fully understood. Therefore, a deep knowledge of the functions of the RAS at both the testicular and seminal levels could clarify its roles in male infertility and sperm physiology, and the different RAS elements could be used to design tools enabling the diagnosis and/or treatment of male infertility.

Correlation between urinary chromium level and semen quality in men attending an andrology laboratory

Chromium is an essential element that is required for the normal physiology but can be toxic to humans above a certain level. In spite of growing interest in research on chromium exposure to human health consensus about its effect on human, semen quality has not been achieved. The aim of the present study is to evaluate the impact of chromium exposure on semen parameters. A total of 760 males attending andrology laboratory of Tongji Hospital, Wuhan, for routine semen analysis were enrolled and requested to provide semen and urine samples. The urine level of chromium was evaluated using inductively coupled plasma mass spectrometry (ICP-MS), and computer-assisted semen analysis (CASA) was applied to examine semen parameters. Associations between semen parameters and urinary chromium were analyzed by means of multivariate linear regression analysis. Multivariate analysis showed a negative association between the urinary concentrations of chromium and progressive motility (β = - 0.014, p = 0.040) and total motility (β = - 1.077, p = 0.048), while other semen parameters did not show any statistically significant changes. Urinary chromium could influence semen quality parameters and impair male fecundity.

Diagnostic value of advanced semen analysis in evaluation of male infertility

Conventional semen analysis is the standard of care to initially evaluate the fertility status of a male patient. However, it has some limitations and among these are failure to correctly identify the aetiology underlying fertility problems, intra- and inter-observer variability and incomplete information about sperm function. Considering these drawbacks, advanced semen tests have been developed to assess male infertility, including sperm function tests, oxidative stress (OS) and sperm DNA fragmentation (SDF) tests. This review illustrates the commonly utilised sperm function techniques, along with the assays used to assess SDF and OS and their diagnostic value.

Human sperm testicular angiotensin-converting enzyme helps determine human embryo quality

Angiotensin-converting enzyme functions in the male reproductive system, but the extent of its function in reproduction is not fully understood. The primary objective of this work was to investigate the relationship between the testicular isoform of angiotensin-converting enzyme present in human spermatozoa and semen parameters, human embryo quality, and assisted reproduction success. A total of 81 semen samples and 635 embryos from couples undergoing oocyte donation cycles at the IVI Bilbao Clinic were analyzed. Semen parameters, embryos quality, and blastocyst development were examined according to the World Health Organization standards and the Spanish Association of Reproduction Biology Studies criteria. The percentage of testicular angiotensin-converting enzyme-positive spermatozoa and the number of molecules per spermatozoon were analyzed by flow cytometry. Both parameters were inversely correlated with human sperm motility. Higher percentages of testicular angiotensin-converting enzyme-positive spermatozoa together with fewer enzyme molecules per spermatozoon were positively correlated with better embryo quality and development. Our results suggest that embryos with a higher implantation potential come from semen samples with higher percentages of testicular angiotensin-converting enzyme-positive cells and fewer enzyme molecules per spermatozoon. Based on these findings, we propose that testicular angiotensin-converting enzyme could be used to aid embryologists in selecting better semen samples for obtaining high-quality blastocysts during in vitro fertilization procedures.

Knowledge gaps in male infertility: a reproductive endocrinology and infertility perspective

Reproductive research has moved forward at a remarkable pace. Some of these advances are the result of a separation between male and female specialties, allowing focused study in specific areas of the field. However, the different training programs between male and female fertility specialists has created an environment in which some discoveries are not put in the greater context of clinical care. At times, interventions have been measured against surrogate markers of outcome that may not impact the most meaningful outcome for patients—the delivery of a healthy neonate. For example, medical and surgical interventions that use changes in semen parameters may have a limited impact on the likelihood of achieving a live birth due to the limitations inherent in the semen analysis for predicting outcomes. Other commonly used tests, such as sperm DNA fragmentation assays provide promising biological plausibility to account for subfertility of some male partners. However, until well defined thresholds for predicting outcomes in different treatment scenarios are available, changes in sperm DNA fragmentation testing is not an adequate outcome for measuring the utility of interventions. The biggest limitation for these tests remains their analysis of bulk semen. Tests allowing interrogation of the reproductive competence of a given sperm, while allowing that sperm to be used in assisted reproductive technology procedures remain elusive. Progress toward reaching this end (whether by hyaluronic acid binding, IMSI, or Ramen spectroscopy) is underway, but much remains to be learned. Achieving testing and capture of individual sperm would better facilitate studies that measure the most meaningful outcome for patients and providers—the delivery of a healthy baby.

Computer-aided sperm analysis: a useful tool to evaluate patient's response to varicocelectomy

Preoperative and postoperative sperm parameter values from infertile men with varicocele were analyzed by computer-aided sperm analysis (CASA) to assess if sperm characteristics improved after varicocelectomy. Semen samples of men with proven fertility (n = 38) and men with varicocele-related infertility (n = 61) were also analyzed. Conventional semen analysis was performed according to WHO (2010) criteria and a CASA system was employed to assess kinetic parameters and sperm concentration. Seminal parameters values in the fertile group were very far above from those of the patients, either before or after surgery. No significant improvement in the percentage normal sperm morphology (P = 0.10), sperm concentration (P = 0.52), total sperm count (P = 0.76), subjective motility (%) (P = 0.97) nor kinematics (P = 0.30) was observed after varicocelectomy when all groups were compared. Neither was significant improvement found in percentage normal sperm morphology (P = 0.91), sperm concentration (P = 0.10), total sperm count (P = 0.89) or percentage motility (P = 0.77) after varicocelectomy in paired comparisons of preoperative and postoperative data. Analysis of paired samples revealed that the total sperm count (P = 0.01) and most sperm kinetic parameters: curvilinear velocity (P = 0.002), straight-line velocity (P = 0.0004), average path velocity (P = 0.0005), linearity (P = 0.02), and wobble (P = 0.006) improved after surgery. CASA offers the potential for accurate quantitative assessment of each patient's response to varicocelectomy.

Clinical assessment of the male fertility

The evaluation of infertility in males consists of physical examination and semen analyses. Standardized semen analyses depend on the descriptive analysis of sperm motility, morphology, and concentration, with a threshold level that must be surpassed to be considered a fertile spermatozoon. Nonetheless, these conventional parameters are not satisfactory for clinicians since 25% of infertility cases worldwide remain unexplained. Therefore, newer tests methods have been established to investigate sperm physiology and functions by monitoring characteristics such as motility, capacitation, the acrosome reaction, reactive oxygen species, sperm DNA damage, chromatin structure, zona pellucida binding, and sperm-oocyte fusion. After the introduction of intracytoplasmic sperm injection technique, sperm maturity, morphology, and aneuploidy conditions have gotten more attention for investigating unexplained male infertility. In the present article, recent advancements in research regarding the utilization of male fertility prediction tests and their role and accuracy are reviewed.

Effects of Chronic Musculoskeletal Pain on Fertility Potential in Lean and Overweight Male Patients

Both chronic pain and obesity are known to affect reproductive hormone profiles in male patients. However, the effect of these conditions, alone or in combination, on male fertility potential has received less attention. 20 chronic musculoskeletal pain patients and 20 healthy controls were divided into lean and overweight subgroups according to their BMI. Current level of chronic pain (visual analogue scale) and pressure pain thresholds (PPTs) in 16 predefined sites, classically described and tested as painful points on the lower body, were measured. Levels of reproductive hormone and lipid profiles were assessed by ELISA. Sperm concentration and motility parameters were analyzed using a computer-aided sperm analysis system. Sperm concentration, progressive motility, and percentage of hyperactivated sperm were generally lower in the chronic pain patients in both lean and overweight groups. The overweight control and the lean chronic pain groups demonstrated a significantly lower percentage of progressively motile sperm compared with the lean control group, suggesting that musculoskeletal chronic pain may have a negative influence on sperm quality in lean patients. However, due to the potential great negative influence of obesity on the sperm parameters, it is difficult to propose if musculoskeletal chronic pain also influenced sperm quality in overweight patients. Further research in chronic pain patients is required to test this hypothesis.

Sperm DNA and detection of DNA fragmentations in sperm

The questionable effectiveness of routine sperm parameters in determining male factor infertility problems and increasing the success rates of assisted reproductive techniques have led to the investigation of more detailed sperm parameters that could affect the male fertility and reproduction. Thus, the effects of different sperm parameters such as sperm DNA integrity was started to be investigated thanks to the previously described methods such as single cell gel electrophoresis (COMET) assay, sperm chromatin structure assay (SCSA), acridine orange test (AOT), terminal deoxynucleotidyl transferase-mediated deoxyuridine (TdT) triphosphate (dUTP) nick end labeling (TUNEL) assay and sperm chromatin dispersion (SCD) test. However, studying on sperm DNA might be very complex because the sperm DNA differs from the somatic cell DNA with its unique structure. Also, the sperm DNA undergoes many changes during spermatogenesis and it is condensed by being packaged tightly with different types and numbers of protamines in different species. Despite all these difficulties, these methods provide important information about the reasons and consequences of DNA damages in sperm and the effects of these damages on reproduction.

On the Origins of the Semen Analysis: A Close Relationship with the History of the Reproductive Medicine

The spermatozoa were first seen in ejaculates in the 17^th century. However, the basic mechanisms of human fertilization have been only fully understood after the discovery of ovum in 1827. As a result, the interest in developing technologies for semen analysis arose from the early 1900s. Indeed, standard methodologies for semen analysis were designed mostly along the first half of the 20^th century. Before the 1930s, semen analysis was nearly unavailable clinically, since there were still no robust methodologies for assessing sperm characteristics, as well as to set up standard references that could be able to assess the reproductive capacity of men. However, joining some methodologies reported from 1910 up to 1930, standardization was attained and thereby semen analysis increasingly assumed its role in laboratory practice for investigating men in barren marriage. This article aims in reviewing historical backgrounds on the semen analysis, up to its insertion in laboratory practice. Emphasis is given to the major studies that contributed either directly or indirectly in developing the earliest routine for the semen analysis.

Oxidative DNA Damage to Sperm Cells and Peripheral Blood Leukocytes in Infertile Men

BACKGROUND Oxidative DNA damage is associated with male infertility. The aim of this study was to evaluate the oxidative DNA damage of sperm cells and blood leukocytes and to determine the levels of MDA and NO levels in seminal and blood plasma of idiopathic infertile men. MATERIAL AND METHODS The study enrolled 52 patients, including 30 infertile and 22 fertile men. MDA, NO, and 8-OHdG/106dG were estimated using spectrophotometry and high-pressure liquid chromatography (HPLC)-based methods in seminal and blood plasma. The association with the sperm parameters was assessed, particularly sperm counts and motility. RESULTS The mean sperm concentration and sperm motility of the fertile men were significantly higher than that of the infertile men. The mean MDA and NO concentration in the seminal and blood samples of the infertile men were higher than that of fertile men. Also, the mean numbers of sperm cells and leukocytes 8-OHdG/106dG of the infertile men were significantly higher than that of fertile men (p=0.04 and p<0.001, respectively). Sperm motility and sperm count were negatively correlated with leukocyte and sperm cell 8-OHdG/106dG ratio. However, progressive motility was significantly negatively correlated with sperm cell and leukocyte 8-OHdG/106dG ratio (R=-0.357, p=0.026; R=-0.388, p=0.024, respectively). CONCLUSIONS Oxidative stress is an important factor in male infertility. Therefore, biochemical detection of 8-OHdG/106dG in sperm cells and blood leukocytes may be an additional tool in the diagnosis of male infertility.

Total antioxidant status and lipid peroxidation with and without in vitro zinc supplementation in infertile men

The aim of this study was to assess the total antioxidant capacity (TAC) and malondialdehyde (MDA) level in infertile men with asthenozoospermia and asthenoteratozoospermia compared to fertile donors, and to examine the effect of zinc on sperm lipid peroxidation and antioxidant status in infertile and fertile men. Semen samples provided by infertile men (n = 38) and fertile donors (controls; n = 12) were exposed to 6 mmol/L of zinc for 2 hr at 37°C. After semen analysis, lipid peroxidation was detected by MDA assay and seminal TAC was assessed by colorimetric method using TAS (total antioxidant status) Kit. TAC was significantly lower in infertile group compared to controls (p = .037). However, lipid peroxidation did not alter in infertile patients compared to controls (p > .05). After in vitro incubation of samples with zinc, a significant increase in TAC level was found only in infertile men (p < .001). Meanwhile, zinc had no effect on sperm lipid peroxidation in both fertile and infertile men (p > .05). Our data indicate that antioxidant treatment based on zinc in vitro supplementation may be helpful to enhance the rate of seminal antioxidant status in infertile men; however, it does not prevent sperm lipid peroxidation.

Conventional and fluorescent based semen quality assessment in Karan Fries bulls

Aim:

The present study was carried out on semen ejaculates of 15 Karan Fries (KF) bulls maintained at Artificial Breeding Research Centre, National Dairy Research Institute, Karnal, India with an objective to evaluate the relationship between the conventional and fluorescent based semen quality analysis of the bulls.

Materials and Methods:

A total of 96 ejaculates were collected from 15 KF (Holstein Friesian [HF] crossbred) bulls. Semen were evaluated for color, volume, mass activity (MA) and percentage of individual motility (IM), sperm concentration, percent live spermatozoa, hypo-osmotic swelling test and acrosome integrity, chromatin integrity, sperm viability, and membrane integrity. Data were analyzed using SPSS software package for descriptive analysis. The correlation between rankings of sires based on conventional and fluorescent semen parameters were calculated by Spearman’s rank correlation coefficient.

Results:

The average ejaculates volume (ml), sperm concentration (10⁶/ml), MA, IM (%), live (%), morphological abnormalities (%), host (%), acrosome integrity (%), chromomycin A3 (CMA3) (%), SYBR-PI (%), and fluorescent isothiocyanate-peanut agglutinin (FITC-PNA) (%) were 4.57±0.36, 1162.98±97.93, 2.95±0.09, 60.8±1.22, 71.41±2.10, 9.31±1.15, 65.5±1.81, 86.6±1.59, 3.53±0.43, 65.39±2.23 and 74.47±2.53, respectively. Rank correlations were found to be significant for SYBR-PI and FITC-PNA with most of the parameters evaluated by conventional methods. Overall, among conventional criteria, IM revealed ranking of bulls almost similar to that of fluorescent criteria.

Conclusion:

Overview of our results indicated that, among conventional criteria, MA and IM revealed ranking of bulls almost similar to that of fluorescent criteria.

Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay using bench top flow cytometer for evaluation of sperm DNA fragmentation in fertility laboratories: protocol, reference values, and quality control

PURPOSE

The purpose of this study is to provide a detailed protocol and quality control steps for measuring sperm DNA fragmentation (SDF) by terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) assay using a new bench top flow cytometer, determine the reference value of SDF, and assess sensitivity, specificity, and distribution of SDF in infertile men and controls with proven and unproven fertility.

METHODS

Semen specimens from 95 controls and 261 infertile men referred to a male infertility testing laboratory were tested for SDF by TUNEL assay using Apo-Direct kit and a bench top flow cytometer. Percentage of cells positive for TUNEL was calculated. Inter- and intraobserver variability was examined. TUNEL cutoff value, sensitivity, specificity, and distribution of different cutoff values in controls and infertile patients were calculated.

RESULTS

The reference value of SDF by TUNEL assay was 16.8 % with a specificity of 91.6 % and sensitivity of 32.6 %. The positive and negative predictive values were 91.4 and 33.1 %, respectively. The upper limit of DNA damage in infertile men was significantly higher (68.9 %) than that in the controls (19.6 %).

CONCLUSIONS

TUNEL assay using flow cytometry is a reproducible and easy method to determine SDF. At a cutoff point of 16.8 %, the test showed high specificity and positive predictive value. The results of this test could identify infertile men whose sperm DNA fragmentation does not contribute to their infertility and confirm that a man who tests positive is likely to be infertile due to elevated sperm DNA fragmentation.

PRODUÇÃO IN VITRO DE EMBRIÕES UTILIZANDO-SE SÊMEN SEXADO DE TOUROS 5/8 GIROLANDO

<title>Resumo</title><p>Avaliou-se a taxa de produção de blastocisto <italic>"in vitro"</italic>utilizando-se o sêmen bovino sexado. Foram utilizados três reprodutores para verificar a variação individual do sêmen, taxas de clivagem e produção embrionária. O trabalho utilizou-se de biotécnicas reprodutivas, análise computadorizada do sêmen pós-descongelação e sondas fluorescentes para análises de integridade da célula espermática (membrana plasmática, membrana acrossomal e potencial mitocondrial). Um total de 959 oócitos passou por etapas de maturação <italic>in vitro,</italic> fertilização <italic>in vitro</italic> (sexado, n= 473; convencional, n = 486) e cultivo <italic>in vitro</italic>. A taxa de clivagem foi observada no D2 e a de blastocistos no D7. Os dados foram analisados pelo programa SPSS 16.0 empregando-se a análise de variância (ANOVA), sendo o teste t-Student usado para detectar diferenças entre os grupos e o Qui-quadrado para análise dos resultados da produção <italic>in vitro</italic>(P< 0,05). Os resultados diferiram entre o sêmen convencional (31,06%) e sexado (21,10%) para produção de blastocisto. Quando comparada a produção de blastocisto individualmente nas amostras de sêmen sexado (27,69%; 17,93% e 25,56%, touros 1, 2 e 3, respectivamente), percebeu-se que T2 < T1 e T1=T3 e T2=T3. Quanto às análises de cinética espermática, as amostras de sêmen sexado mostraram diferenças entre os touros nas variáveis velocidade curvilínea, velocidade linear e velocidade do trajeto em que o T1(117,7±1,6 µm/s; 60,0±0,3 µm/s; 73,6±0,4 µm/s, respectivamente) quando comparado aos touros T2 (80,2±2,3 µm/s; 47,0±2,0 µm/s; 57,7±0,9 µm/s, respectivamente) e T3 (86,4±5,7 µm/s; 46,2±2,7 µm/s; 53,8±2,8 µm/s, respectivamente) obteve valores mais elevados. As análises da integridade da célula espermática não diferiram entre as amostras de sêmen convencional, já no sêmen sexado a integridade de membrana foi a variável que diferiu estatisticamente entre os touros, em que o T1 (38 ±2,7) diferiu do T3(53,8± 1,8) (P=0,009), mas não divergiu do T2 (44,1±4,4). É possível concluir que o sêmen sexado foi menos eficiente na produção de blastocisto quando comparado ao sêmen convencional. As análises de cinética e de integridade foram compatíveis com o potencial fertilizante das amostras de sêmen em touros da raça 5/8 Girolando.</p>

Total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta are significantly correlated with fertilization rates after intracytoplasmic sperm injection

OBJECTIVE

To study the relationship of total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta, with fertilization rates after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

DESIGN

Laboratory study; controls vs. patients after IVF (n = 27) or ICSI (n = 17) treatment.

SETTING

Fertility center.

PATIENT(S)

A total of 44 semen samples, subjected to either IVF or ICSI treatment. Oocyte collection, ICSI or IVF, determination of sperm concentration and motility, and immunocytochemical analyses of phospholipase C zeta (PLCζ).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Percentages of sperm exhibiting PLCζ.

RESULT(S)

Significant positive correlation between ICSI fertilization rates and total levels, localization patterns, and the proportion (percentage) of sperm exhibiting PLCζ. Total levels, localization patterns, and the proportion of sperm exhibiting PLCζ are correlated with fertilization rates for ICSI, but not for IVF.

CONCLUSION(S)

Evaluating total levels, localization patterns, and proportions of PLCζ may represent a useful diagnostic tool for clinical purposes in men for whom IVF is not advised or has previously failed. This clinical study further supports the fundamental role of PLCζ in the oocyte activation process.

Relationship of spermatozoal DNA fragmentation with semen quality in varicocele-positive men

The aim of the study was to assess the semen quality and levels of spermatozoal nuclear DNA fragmentation in subfertile subjects clinically diagnosed with varicocele, subfertile subjects without varicocele and healthy fertile controls. Semen samples were obtained from 302 subjects. Of them, 115 were healthy fertile controls having normal semen characteristics, 121 subfertile men diagnosed with varicocele, both, clinically and on ultrasonography, while 66 subjects were subfertile with no varicocele. Spermatozoal concentration, percentage motility, morphology and DNA fragmentation were measured. In the study population, deterioration in semen quality-decreased spermatozoal concentration, percentage motility and normal morphology was seen in subfertile subjects, especially with varicocele. Highest spermatozoal DNA fragmentation was observed in varicocele-positive subjects as compared with varicocele-negative subjects and healthy fertile controls. Significant negative correlation was seen between spermatozoal DNA fragmentation and concentration (r = -0.310), motility (r = -0.328) normal morphology, WHO method (r = -0.221) and Tygerberg strict criteria (r = -0.180) in the varicocele-positive subfertile subjects. In conclusion, this study suggests existence of a negative relationship between spermatozoal DNA fragmentation and semen quality in varicocele-positive subfertile subjects.

A translational medicine appraisal of specialized andrology testing in unexplained male infertility

The diagnostic and prognostic validity of sperm function biomarkers is particularly relevant for males with unexplained infertility in which routine semen analysis fails to detect subcellular sperm dysfunctions. In this general review, we examine the role and significance of specialized andrology laboratory tests from past to present and provide a glance toward the future. We concluded that the assessment of sperm DNA damage and oxidative stress provide a relatively independent measure of fertility that yields diagnostic and prognostic information complementary to, but distinct and more significant than, standard sperm parameters. Since none of the available methods for such testing have been fully translated, further research is necessary to evaluate their cost-effectiveness when applied in large scale to daily medical practice. Application of translational medicine concepts would also be useful to accelerate the clinical application of recent discoveries in the fields of genomics, proteomics and metabolomics.

Unexplained male infertility: diagnosis and management

Unexplained male infertility is a diagnosis reserved for men in whom routine semen analyses results are within normal values and physical as well as endocrine abnormalities were ruled out. In addition to erectile problems and coital factors, immunologic causes and sperm dysfunction may contribute to such condition. New etiologies of unexplained male infertility include low level leukocytospermia and mitochondrial DNA polymerase gene polymorphism. Contemporary andrology may reveal cellular and sub-cellular sperm dysfunctions which may explain subfertility in such cases, thus aiding the clinician to direct the further work-up, diagnosis and counseling of the infertile male. The objective of this article is to highlight the concept of unexplained male infertility and focuses on the diagnosis and treatment of this condition in the era of modern andrology and assisted reproductive techniques. Extensive literature review was performed using the search engines: Pubmed, Science-direct, Ovid and Scopus.

Stallion sperm transcriptome comprises functionally coherent coding and regulatory RNAs as revealed by microarray analysis and RNA-seq

Mature mammalian sperm contain a complex population of RNAs some of which might regulate spermatogenesis while others probably play a role in fertilization and early development. Due to this limited knowledge, the biological functions of sperm RNAs remain enigmatic. Here we report the first characterization of the global transcriptome of the sperm of fertile stallions. The findings improved understanding of the biological significance of sperm RNAs which in turn will allow the discovery of sperm-based biomarkers for stallion fertility. The stallion sperm transcriptome was interrogated by analyzing sperm and testes RNA on a 21,000-element equine whole-genome oligoarray and by RNA-seq. Microarray analysis revealed 6,761 transcripts in the sperm, of which 165 were sperm-enriched, and 155 were differentially expressed between the sperm and testes. Next, 70 million raw reads were generated by RNA-seq of which 50% could be aligned with the horse reference genome. A total of 19,257 sequence tags were mapped to all horse chromosomes and the mitochondrial genome. The highest density of mapped transcripts was in gene-rich ECA11, 12 and 13, and the lowest in gene-poor ECA9 and X; 7 gene transcripts originated from ECAY. Structural annotation aligned sperm transcripts with 4,504 known horse and/or human genes, rRNAs and 82 miRNAs, whereas 13,354 sequence tags remained anonymous. The data were aligned with selected equine gene models to identify additional exons and splice variants. Gene Ontology annotations showed that sperm transcripts were associated with molecular processes (chemoattractant-activated signal transduction, ion transport) and cellular components (membranes and vesicles) related to known sperm functions at fertilization, while some messenger and micro RNAs might be critical for early development. The findings suggest that the rich repertoire of coding and non-coding RNAs in stallion sperm is not a random remnant from spermatogenesis in testes but a selectively retained and functionally coherent collection of RNAs.

Genome-wide association study implicates testis-sperm specific FKBP6 as a susceptibility locus for impaired acrosome reaction in stallions

Impaired acrosomal reaction (IAR) of sperm causes male subfertility in humans and animals. Despite compelling evidence about the genetic control over acrosome biogenesis and function, the genomics of IAR is as yet poorly understood, providing no molecular tools for diagnostics. Here we conducted Equine SNP50 Beadchip genotyping and GWAS using 7 IAR–affected and 37 control Thoroughbred stallions. A significant (P<6.75E-08) genotype–phenotype association was found in horse chromosome 13 in FK506 binding protein 6 (FKBP6). The gene belongs to the immunophilins FKBP family known to be involved in meiosis, calcium homeostasis, clathrin-coated vesicles, and membrane fusions. Direct sequencing of FKBP6 exons in cases and controls identified SNPs g.11040315G>A and g.11040379C>A (p.166H>N) in exon 4 that were significantly associated with the IAR phenotype both in the GWAS cohort (n = 44) and in a large multi-breed cohort of 265 horses. All IAR stallions were homozygous for the A-alleles, while this genotype was found only in 2% of controls. The equine FKBP6 was exclusively expressed in testis and sperm and had 5 different transcripts, of which 4 were novel. The expression of this gene in AC/AG heterozygous controls was monoallelic, and we observed a tendency for FKBP6 up-regulation in IAR stallions compared to controls. Because exon 4 SNPs had no effect on the protein structure, it is likely that FKBP6 relates to the IAR phenotype via regulatory or modifying functions. In conclusion, FKBP6 was considered a susceptibility gene of incomplete penetrance for IAR in stallions and a candidate gene for male subfertility in mammals. FKBP6 genotyping is recommended for the detection of IAR–susceptible individuals among potential breeding stallions. Successful use of sperm as a source of DNA and RNA propagates non-invasive sample procurement for fertility genomics in animals and humans.

Impaired acrosomal reaction (IAR) of sperm causes male subfertility in humans and animals, and currently the molecular causes of the condition are not known. Here we report the mapping, identification, and functional analysis of a susceptibility locus for IAR in stallions. The candidate region was mapped to horse chromosome 13 by SNP genotyping and GWAS of 7 IAR affected and 44 control Thoroughbred stallions. Re-sequencing and case-control analysis of functionally relevant candidate genes in the region identified FKBP6 gene as a significantly associated locus. The association was confirmed by genotyping 265 male horses of multiple breeds. FKBP6 belongs to the immunophilins FKBP family known to be involved in meiosis, calcium homeostasis, clathrin-coated vesicles, and membrane fusions. We showed that the equine FKBP6 is exclusively and monoallelically expressed in testis and sperm and has 5 different transcripts, of which 4 were novel. Overall, FKBP6 was considered a susceptibility gene of incomplete penetrance for IAR in stallions and a candidate gene for male subfertility in other mammals. Successful use of sperm as a source of DNA and RNA propagates non-invasive sample procurement for fertility genomics in animals and humans.

Differences in blood and semen oxidative status in fertile and infertile men, and their relationship with sperm quality

Oxidative stress plays a fundamental role in the aetiology of male infertility by negatively affecting sperm quality and function. Assessment of blood and seminal plasma oxidative profiles might be a valuable tool to improve evaluation of sperm reproductive capacity and functional competence. This study examined the lipid-soluble antioxidant profile and levels of lipid peroxidation both in blood and seminal plasma samples of infertile and fertile males, in relation to semen parameters. Total antioxidant capacity (TAC) and vitamin E concentrations were significantly (P<0.05) lower in seminal plasma of infertile men compared with fertile subjects; concurrently, a significant accumulation of malondialdehyde was found in infertile patients (P=0.032 compared with controls), which was negatively correlated with sperm motility and morphology. In blood samples, infertile men presented lower concentrations of TAC, carotenoids and vitamin E than fertile subjects; TAC and carotenoids were positively correlated with sperm motility, morphology and concentration. Finally, blood TAC and vitamin E concentrations were positively correlated with the corresponding seminal values, confirming the close relationship between blood and semen antioxidants. All these results indicated the possibility of using not only seminal antioxidants but also blood antioxidants as biochemical markers to support sperm quality evaluation. Oxidative stress induced by reactive oxygen species (ROS) has been widely recognized as one of the major causes of male infertility; indeed, excessive ROS production can negatively impact sperm quality and function. The assessment of blood and seminal plasma oxidative profiles has been suggested as a valuable tool to improve the evaluation of sperm reproductive capacity and functional competence in infertile men. With this in mind, in the present study we examined the lipid soluble antioxidant profile (carotenoids and vitamins A and E) and the levels of lipid peroxidation (malondialdehyde; MDA) both in blood and seminal plasma samples of infertile and fertile males, in correlation with semen parameters namely motility, morphology and concentration. As a result, we obtained evidence that the total antioxidant capacity (TAC) and the concentrations of vitamin E of seminal plasma samples were significantly lower in infertile men than in fertile subjects; at the same time, a significant accumulation of MDA was found in infertile patients. MDA, in turn, negatively correlated with sperm motility and morphology, thus confirming that oxidative damage to lipids impairs sperm quality. In blood samples, infertile men presented lower TAC and lower concentrations of carotenoids and vitamin E than fertile subjects; interestingly, TAC and carotenoid concentrations were positively correlated with sperm motility, morphology, and concentration, confirming the close relationship between blood antioxidants and sperm quality. In conclusion, all these results suggested that the examination of blood and semen oxidative profiles might furnish useful information on sperm quality and function in infertile men.

Sperm gene expression profile is related to pregnancy rate after insemination and is predictive of low fecundity in normozoospermic men

BACKGROUND

Assessment of male fertility is traditionally based on microscopic evaluation of semen. However, the classical semen parameters do not adequately reflect sperm function, and their clinical value in predicting fertility is limited. We hypothesize that the sperm expression profile could reflect the fertilizing quality of spermatozoa and could be more informative for predicting the in vivo reproductive fitness of men with normal semen parameters.

METHODS

Sperm gene expression patterns of 68 normozoospermic donors (43 Phase I and 25 Phase II), used for therapeutic IUI, were analysed via TaqMan Arrays.

RESULTS

Significant differences in the expression of individual genes were observed between groups of donors with the lowest and highest pregnancy rates (PRs) after IUI. Additionally, we have developed a molecular means to classify the fertility status of semen donors for IUI based on the expression signature of four genes. In the Phase I study, this model had 90% sensitivity and 97% specificity for discriminating donors resulting in low PRs (cut-off value: <13.6%), far better than that obtained from the combination of sperm parameters. The translation of the model was validated in Phase II donors resulting in a sensitivity of 71.5% and a specificity of 78%.

CONCLUSIONS

Our findings contribute to the search for the most valuable genetic markers which are potentially useful as tools for predicting pregnancy. Our expression model could complement classical semen analysis in order to identify sperm donors with a less favourable IUI reproductive outcome despite having normal semen parameters. It may also be useful for the study of sperm function in couples with unexplained infertility.

Involvement of the prostate and testis expression (PATE)-like proteins in sperm-oocyte interaction

BACKGROUND

The prostate and testis expression (PATE)-like family of proteins are expressed mainly in the male genital tract. They are localized in the sperm head and are homologous to SP-10, the acrosomal vesicle protein also named ACRV1. Our aim was to characterize the expression and functional role of three PATE-like proteins in the testis and ejaculated sperm.

METHODS

The expression and localization of PATE-like proteins in human testis biopsies (n= 95) and sperm cells were assessed by RT-PCR, immunohistochemistry and immunofluorescence staining (at least 600 sperm cells per specimen). The function of the PATE protein was tested by the hemizona assay and hamster egg penetration test (HEPT).

RESULTS

PATE and PATE-M genes and proteins were present almost exclusively in germ cells in the testis: immunoflourescence showed that the percentage of germ cells positive for PATE, PATE-M and PATE-B was 85, 50 and 2%, respectively. PATE and PATE-M proteins were localized in the equatorial segment of the sperm head, while PATE-B protein was localized in the post-acrosomal region. A polyclonal antibody (Ab, at 1:50 and 1:200 dilutions) against the PATE protein did not inhibit sperm-zona binding in the hemizona assay (hemizona index of 89.6 ± 10 and 87 ± 36%, respectively). However, there was inhibition of sperm-oolemma fusion and penetration in the HEPT (penetration index: without Ab 7 ± 3.9; Ab dilution of 1:100, 4 ± 3.5; Ab dilution of 1:20, 0.6 ± 1.2, P < 0.001).

CONCLUSIONS

Our data suggest that PATE protein is involved in sperm-oolemma fusion and penetration but not sperm-zona binding.

Transforming growth factor beta 1 induces tight junction disruptions and loss of transepithelial resistance across porcine vas deferens epithelial cells

Epithelial cells lining the male excurrent duct contribute to male fertility by employing a number of physiological mechanisms that generate a luminal microenvironment conducive to spermatozoa maturation and storage. Among these mechanisms, male duct epithelia establish intercellular tight junctions that constitute a barrier to paracellular diffusion of water, solutes, large molecules, and cells. Mechanisms regulating the male duct epithelial barrier remain unidentified. Transforming growth factor beta (TGFB) is a regulatory cytokine present in high concentrations in human semen. This study examined whether TGFB has any effects on epithelial function exhibited by primary cultures of porcine vas deferens epithelia. TGFB1 exposure caused a 70%-99% decrease in basal transepithelial electrical resistance (R(TE), a sensitive indicator of barrier integrity), while a significant decrease in anion secretory response to forskolin was detected at the highest levels of TGFB1 exposure employed. SB431542, a selective TGFB receptor I (TGFBR1) inhibitor, prevented decreases in barrier function. Results also demonstrated that TGFB1 exposure modifies the distribution pattern of tight junction proteins occludin and claudin 7. TGFBR1 is localized at the apical border of the native porcine vas deferens epithelium. Pharmacological inhibition of mitogen-activated protein kinase (MAPK) 11 (also known as p38-MAPK) did not alter the effect of TGFB1 on R(TE) significantly. These data suggest that epithelia lining the vas deferens are subject to disruptions in the physical barrier if active TGFB becomes bioavailable in the luminal fluid, which might be expected to compromise fertility.