An analysis of sperm function in cases of unexplained infertility: conventional criteria, movement characteristics, and fertilizing capacity

Mass Sperm Motility Is Correlated to Sperm Motility as Measured by Computer-Aided Sperm Analysis (CASA) Technology in Farmed Ostriches

Semen analyses have gained momentum in various livestock industries. However, in farmed ostriches, semen analysis is still in its experimental stage, and males are not screened for sperm quality before breeding. This study investigated the correlations between computer-aided sperm analysis (CASA) technology and the traditional, yet affordable, mass sperm motility score. Semen was collected from nine South African Black ostrich males (mean age ± SD: 5.25 ± 1.21 years), using the dummy female method for 5 consecutive days monthly, for 8 months. Mass sperm motility scores were recorded on a scale of 1−5 (1: little to no sperm movement; 5: rapid sperm movement). The CASA traits recorded were: total motility (MOT), progressive motility (PMOT), curve−linear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), amplitude of lateral head displacement (ALH), linearity (LIN), straightness (STR), wobble (WOB), and beat-cross frequency (BCF). The results revealed positive correlations between mass sperm motility and PMOT, MOT, VCL, and VAP ranging from 0.34 to 0.59 (p < 0.0001). In contrast, negative correlations were recorded between mass sperm motility and LIN, STR, and BCF, with correlations ranging from −0.20 to −0.39 (p < 0.0001). VSL, ALH, and WOB were not correlated to mass sperm motility (p > 0.05). Ostrich farmers may thus be able to evaluate sperm motility reliably and potentially select breeding males by using the affordable mass sperm motility scoring method. Determining the correlation between these methods and fertility after artificial insemination or natural mating is however needed.

CASA-Mot technology: how results are affected by the frame rate and counting chamber

For over 30 years, CASA-Mot technology has been used for kinematic analysis of sperm motility in different mammalian species, but insufficient attention has been paid to the technical limitations of commercial computer-aided sperm analysis (CASA) systems. Counting chamber type and frame rate are two of the most important aspects to be taken into account. Counting chambers can be disposable or reusable, with different depths. In human semen analysis, reusable chambers with a depth of 10µm are the most frequently used, whereas for most farm animal species it is more common to use disposable chambers with a depth of 20µm . The frame rate was previously limited by the hardware, although changes in the number of images collected could lead to significant variations in some kinematic parameters, mainly in curvilinear velocity (VCL). A frame rate of 60 frames s-1 is widely considered to be the minimum necessary for satisfactory results. However, the frame rate is species specific and must be defined in each experimental condition. In conclusion, we show that the optimal combination of frame rate and counting chamber type and depth should be defined for each species and experimental condition in order to obtain reliable results.

Deficiency in Sperm-Egg Protein Interaction as a Major Cause of Fertilization Failure

Complete elucidation of fertilization process at molecular level is one of the unresolved challenges in sexual reproduction studies, and understanding the molecular mechanism is crucial in overcoming difficulties in infertility and unsuccessful in vitro fertilization. Sperm-oocyte interaction is one of the most remarkable events in fertilization process, and deficiency in protein-protein interactions which mediate this interaction is a major cause of unexplained infertility. Due to detection of how the various defects of sperm-oocyte interaction can affect fertilization failure, different experimental methods have been applied. This review summarizes the current understanding of sperm-egg interaction mechanism during fertilization and also accumulates the different types of sperm-egg interaction abnormalities and their association with infertility. Several detection approaches regarding sperm-egg protein interactions and the associated defects are reviewed in this paper.

Interleukin-1β, cyclooxygenase-2, and hypoxia-inducible factor-1α in asthenozoospermia

Impaired male fertility may have a variety of causes, among which asthenozoospermia. In its etiology, several bioactive substances, such as cytokines may be involved. In this context, our aim was to evaluate the expression of interleukin-1β, cyclooxygenase-2, and hypoxia-inducible factor-1α, in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients. We evaluated twenty-eight infertile patients affected by idiopathic asthenozoospermia and twenty-three normospermic fertile donors, age-matched. Sperm parameters were evaluated; immunohistochemical analysis and enzyme-linked immunosorbent assay were then performed in isolated spermatozoa. Spermatozoa from the asthenozoospermic group presented an increased expression of IL-1β, COX-2, and HIF-1α compared with the normospermic fertile subjects. Our results can lead us to speculate that the increased expression of these substances may influence sperm motility. Nevertheless, further studies are needed in order to assess whether these bioactive mediators have a potential relevance as targets in future therapeutic strategies for the treatment of male infertility.

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.

Analysis of endothelial nitric oxide synthase (eNOS) G894T polymorphism and semen parameters in a Chinese Han population

Previous studies have shown that endothelial nitric oxide synthase (eNOS) gene may be involved in abnormal semen parameters. However, the relationship between eNOS G894T polymorphism and semen parameters remains controversial. The purpose of this study was to investigate the association of eNOS G894T polymorphism and semen parameters. The genotype frequency of eNOS G894T was determined in 270 idiopathic asthenozoospermia patients and 248 ethnically matched healthy volunteers using iPLEX genotyping assays on a MassARRAY(®) (Sequenom, San Diego, CA, USA) platform. The statistical analysis performed with Fisher's exact test showed no significant difference in frequencies of genotypes between both groups. The logistic regression showed that genotypes GT, TT and allele T were nonassociated with increased risk of asthenozoospermia in the patient group with ≤5% or >5% sperm with normal forms. The dependence on genotypes of semen parameters was further investigated in both patients and control group. There was no significant difference as compared to control group (P > 0.05). Our study indicated that eNOS gene G894T polymorphism may not have an adverse effect on semen parameters in a Chinese Han population.

Nitric oxide synthase and tyrosine nitration in idiopathic asthenozoospermia: an immunohistochemical study

OBJECTIVE

To characterize the expression pattern of constitutive and inducible nitric oxide synthase (NOS) in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients, by means of immunohistochemistry. Also to evaluate the immunohistochemical expression of citrulline, a marker of NOS activity, and nitrotyrosine, which indicates the formation of peroxynitrite, which may affect sperm functionality through its cytotoxic action.

DESIGN

Prospective study.

SETTING

Academic male infertility center.

PATIENT(S)

Twenty-nine infertile patients affected by idiopathic asthenozoospermia and 26 age-matched normospermic fertile donors.

INTERVENTION(S)

Sperm parameters were evaluated, and immunohistochemical analysis was performed in isolated spermatozoa.

MAIN OUTCOME MEASURE(S)

Semen analyses, to ascertain volume, sperm count, motility, and morphology. Immunohistochemical expression of NOS isoforms, citrulline, and nitrotyrosine.

RESULT(S)

Constitutive NOS expression was greater in spermatozoa isolated from normospermic fertile donors. In contrast, the immunohistochemical expression of inducible NOS and nitrotyrosine was higher in asthenozoospermic samples. Our data concerning citrulline indicated enhanced NOS activity in sperm from idiopathic asthenozoospermic patients.

CONCLUSION(S)

Our results support the hypothesis that increased NOS activity and an excess of tyrosine nitration may affect the functional characteristics of spermatozoa in idiopathic asthenozoospermia.

Assessment of sperm quality traits in relation to fertility in boar semen

Background

Several studies have been published where sperm plasma membrane integrity correlated to fertility. In this study we describe a simple fluorometer-based assay where we monitored the fluorescence intensity of artificially membrane-ruptured spermatozoa with a fixed time staining with fluorescent DNA dyes.

Methods

Membrane-impermeant fluorescent dyes Hoechst 33258 (H258) and propidium iodide (PI) were used to measure the fluorescence of the nucleus in artificially membrane ruptured spermatozoa and membrane-permeant dye Hoechst 33342 (H342) was used to measure fluorescence of intact spermatozoa. The concentration of spermatozoa in insemination doses varied from 31.2 × 10⁶/ml to 50 × 10⁶/ml and the average value was 35 × 10⁶/ml. Each boar was represented by three consecutive ejaculates, collected at weekly intervals. Nonreturn rate within 60 days of first insemination (NR %) and litter size (total number of piglets born) of multiparous farrowings were used as fertility measures.

Results

Sperm fluorescence intensity of H258 and H342, but not the fluorescence intensity of PI-stained spermatozoa correlated significantly with the litter size of multiparous farrowings, values being r = - 0.68 (P < 0.01) for H258, r = - 0.69 (P < 0.01) for H342 and r = - 0.38, (P = 0.11) for PI.

Conclusions

The increase in fluorescence values of membrane-ruptured H258 and unruptured H342-stained spermatozoa in boar AI doses can be associated with smaller litter size after AI. This finding indicates that the fluorescence properties of the sperm nucleus could be used to select for AI doses with greater fertilizing potential.

REVISION OF HYPO-OSMOTIC SWELLING (HOS) TEST WITH A PROPOSITION OF CLASSIFIED GRADING SYSTEM: iTS COMPARISONS WITH FOUR DIFFERENT TYPES OF HUMAN SPERM SEPARATION TECHNIQUE

In this study, we arbitrarily classified the morphological changes of sperm under hypo-osmotic condition and compared the results with four different sperm separation techniques. The morphology of classification ranged from a good swelling (SG 3 > SG 2 > SG 1), to non-swelling but reactive (SG 0-R), and completely non-swelling (SG 0). Thirty fresh semen from patients were divided into 4 groups and each processed by washing, swim up, 2-layer column and real time micro-separation system. The prevalent patterns of the swollen sperm in sequence after treatment was SG 0 > SG 1 > SG 3 > SG2 > SG 0-R in fresh semen, and the proportion of SG 0 was almost half of the total % HOS test results. However, SG 3 became the most common swollen form with a significant increase in number with any method of sperm preparation after treatment. The real time technique yielded the highest % rate of SG 3 type of swollen spermatozoa and was the richest in concentration (53+/-3.9%, P < 0.05) as compared with that of swim up (26+/-4.6%), 2-layer (20+/-4.4%), sperm washing (23+/-3.9%), and fresh semen (17+/- 2.8%), respectively. By contrast, 2-layer collected more number of SG0-R (5.3+/-1.2%, P < 0.05) pattern of spermatozoa when compared to real time and swim up. A positive correlation (r = 0.81, P < 0.002) was shown between the % total HOS spermatozoa and total motility of fresh semen but not with morphology. Collectively, an abnormally functional sperm may exist in almost half of a total sperm count from men. It would appear that a better potential fertilization capacity may reside in the more swollen sperm from HOS test than the less swollen sperm and that may be more related with the motility rather than the morphology. The HOS classification and grading system appears valuable in further evaluating sperm quality.

Semen banking—is it now feasible for captive endangered species?

This article proposes that serious consideration should now be given to the establishment of banks of genetic material from rare and endangered species. In the light of advances in the technology associated with semen assessment and preservation, the limitations that have so far discouraged the practice of semen freezing and banking can now be minimized and circumvented. The authors review these developments and suggest that semen preservation should be reconsidered as a practical means of preserving the genetic diversity currently contained within captive stocks of wild animals.

Laboratory standards in routine clinical andrology

It is a fundamental principle of laboratory tests that they are never entirely free from error. However, understanding the source and extent of such errors is a prerequisite for correct appreciation and interpretation of test results in the diagnostic process. In order to evaluate these errors, quality control (QC) has been introduced into clinical laboratory tests and has become routine practice.

Free thiols in human spermatozoa: are Na+/K+-ATPase, Ca2+-ATPase activities involved in sperm motility through peroxynitrite formation?

The aim of the present study was to measure free thiols content, Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities in human spermatozoa of asthenozoospermic patients and normospermic donors, and evaluate any influence on kinetic sperm features, as well as correlation with peroxynitrite. In fact, membrane integrity and its composition are the basic characteristics of the sperm membrane; thus, it is evident that its composition is an important factor for membrane functions that can be modified upon oxidation. A total of 70 infertile patients affected by idiopathic asthenozoospermia and 25 normal fertile donors were enrolled. Control spermatozoa exhibited Na(+)/K(+)-ATPase, and Ca(2+)-ATPase activities, cytoplasmic Ca(2+) concentration and free -SH content significantly higher than those of asthenozoospermic patients (P < 0.0001). Moreover, positive associations were found between Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities and total sperm motility and sperm kinetic features, whereas negative associations were found between peroxynitrite and Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities, and total SH content. Peroxynitrite is able to reduce Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities and intracellular Ca(2+) concentration, through possible depletion of free thiols content. Decrease in motility and loss of sperm function in idiopathic asthenozoospermia can be attributed to these sulphydryl groups, important entities of the sperm membrane.

Applications and interpretation of computer-assisted sperm analyses and sperm sorting methods in assisted breeding and comparative research

Theoretical and practical knowledge of sperm function is an essential requirement in almost every aspect of modern reproductive technology, if the overarching objective is the eventual production of live offspring. Artificial insemination (AI) techniques depend on the availability of high quality semen, whether fresh, diluted and stored, or frozen. Assessing such semen for quality and the likelihood of fertility is therefore also important, as much time, resources and effort can easily be wasted by using poor samples. Some semen technologies are aimed not at quality assessment, but at attempting to skew the breeding outcomes. Sex preselection by separating the male- and female-bearing spermatozoa using flow cytometry is now practised routinely in the agricultural industry, but speculatively it may eventually be possible to use other genetic markers besides the sex chromosomes. A moment's reflection shows that although sex-biasing flow cytometry technology is well developed and generally fulfils its purpose if presorting of sperm quality is adequate, other technologies aimed specifically at semen assessment are also sophisticated but provide inadequate data that say little about fertility. This is especially true of instrumentation for objective sperm motility assessment. Here we aim to examine this technological paradox and suggest that although the sperm assessment equipment might be sophisticated, the shortcomings probably lie largely with inappropriate objectives and data interpretation. We also aim to review the potential value and use of sperm sexing technology for non-domestic species, arguing in this case that the limitations also lie less with the technology itself than with the applications envisaged. Finally, the potential application of a sorting method directed at motility rather than sperm DNA content is discussed.

Capacitation-associated protein tyrosine phosphorylation and membrane fluidity changes are impaired in the spermatozoa of asthenozoospermic patients

Sperm protein tyrosine phosphorylation has been associated with capacitation, motility changes, zona binding, and fertilizing ability. We previously demonstrated that gradient-isolated human sperm subpopulations differ in their plasma membrane composition, their ability to phosphorylate proteins in tyrosine residues, and their capacity to undergo hyperactivation. In this study, we have characterized capacitation-associated changes in protein tyrosine phosphorylation and membrane fluidity in spermatozoa of asthenozoospermic and normozoospermic patients consulting for infertility. Semen samples were studied at baseline and after a capacitating incubation with or without the addition of a permeable cAMP analog and a phosphodiesterase inhibitor. Basic sperm and computer-assisted motion parameters, hyperactivation, protein tyrosine phosphorylation (immunofluorescence and Western blot), and membrane fluidity (fluorescent Laurdan probe) were the main study parameters. In comparison with normozoospermic and proven-fertile donor semen, asthenozoospermic samples showed lower motility, velocity, and amplitude of lateral head displacement, both originally and after a 6-h capacitating incubation. Unlike those in normal samples, asthenozoospermic spermatozoa were unable to increase protein tyrosine phosphorylation during capacitation. Such impairment, however, was overcome when they were incubated with a membrane-permeable cAMP analog and a phosphodiesterase inhibitor, indicating a possible membrane defect. Confirming this hypothesis, plasma membranes of asthenozoospermic sperm showed decreased fluidity (increased Laurdan polarization), even after a capacitating incubation. In conclusion, spermatozoa from functional asthenozoospermic samples may owe their poor motility, and their inability to properly capacitate and develop hyperactivation, to an impairment in the tyrosine phosphorylation of critical proteins caused by decreased membrane fluidity. These findings suggest a molecular pathogenetic mechanism for a common seminal pathology associated with male infertility.

Intracytoplasmic sperm injection as a treatment for unexplained total fertilization failure or low fertilization after conventional in vitro fertilization

OBJECTIVE

To determine whether IVF or intracytoplasmic sperm injection (ICSI) should be the choice of treatment in case of a previous IVF attempt with unexplained total fertilization failure or low fertilization (<25%).

DESIGN

Prospective study.

SETTING

Leiden University Medical Center.

PATIENT(S)

Thirty-eight couples undergoing IVF and ICSI on sibling oocytes after a first IVF attempt with total fertilization failure or with low fertilization (<25%).

INTERVENTION(S)

Performing IVF and ICSI on sibling oocytes.

MAIN OUTCOME MEASURE(S)

Fertilization and (ongoing) pregnancy rate.

RESULT(S)

A total of 271 oocytes were collected in 24 oocyte retrievals in the total fertilization failure group. Hundred nine oocytes were randomly allocated to IVF and 12 were fertilized (11%); 162 sibling oocytes were allocated to ICSI and 78 were fertilized (48%). In 8 of the 24 patients fertilization occurred after IVF. The pregnancy rate after transfer of 1 IVF and 1 ICSI embryo (n = 3) was 67% and after the transfer of 2 ICSI embryos (n = 21) this was 52%. In the low fertilization group 169 oocytes were collected in 14 oocyte retrievals. Seventy-two oocytes were randomly allocated to IVF and 16 were fertilized (22%). Ninety-seven sibling oocytes were allocated to ICSI and 58 were fertilized (60%). In 7 of 14 patients fertilization occurred after IVF. The pregnancy rate after the transfer of 1 IVF and 1 ICSI embryo (n = 5) was 80% and after the transfer of 2 ICSI embryos (n = 9) this was 33%.

CONCLUSION(S)

Performing ICSI on some oocytes of a cohort may avoid total fertilization failures both in patients with a history of total fertilization failure and in patients with a history of low fertilization, as the percentage of fertilization is higher after ICSI compared to IVF and the recurrence of total fertilization failure and low fertilization is high after IVF treatment.

Use of the Sperm-Class Analyser for objective assessment of human sperm morphology

The Sperm-Class Analyser was validated for assessing morphometric parameters of the head and midpiece of unwashed and washed human ejaculated spermatozoa from volunteers providing a wide range of semen quality. A higher proportion of sperm could be assessed (86% fresh semen and 75% washed sperm) if Hemacolor staining was used rather than DiffQuik (80 and 73%) or Papanicolaou (78 and 68%). Different stains employed different fixatives and the area, length, width and perimeter of the sperm head was significantly larger for washed sperm stained by Hemacolor and DiffQuik. Acrosomal area ranged from 48 to 51% of the sperm head area and this percentage was larger for washed sperm stained with DiffQuik. Sperm at the end of the slide, distant from the initial semen droplet, were larger in area and perimeter than those at that site or in the middle. The high precision and reproducibility of the equipment required assessing only 50 sperm on the slide. Far greater variation was found in head width, relative acrosomal area and midpiece width between different slides prepared from the same ejaculate, highlighting the inherent variability within the ejaculate and smear preparation, and requiring more than one slide to be assessed.

The relationship between environmental exposure to phthalates and computer-aided sperm analysis motion parameters

The general population is exposed to phthalates through consumer products, diet, and medical devices. The present study explored whether phthalates, reproductive toxins in laboratory animals, were associated with altered sperm movement characteristics in men. Two-hundred twenty subjects provided a semen sample for computer-aided sperm analysis (CASA) and a urine sample for measurement of phthalate monoesters, monoethyl (MEP), monobenzyl (MBzP), mono-n-butyl (MBP), mono-2-ethylhexyl (MEHP), and monomethyl (MMP). Three CASA parameters, straight-line velocity (VSL), curvilinear velocity (VCL), and linearity (LIN), were used as measures of sperm progression, sperm vigor, and swimming pattern, respectively. There were suggestive dose-response relationships (shown as the predicted change in mean sperm motion parameter for the second and third tertiles compared with the first tertile; P value for trend) for MBzP with VSL (-2.36 microm/s, -2.81 microm/s; P =.09) and VCL (-1.67 microm/s, -2.45 microm/s; P =.4). There were suggestive negative associations between MBP and VSL (-3.07 microm/s, -2.87 microm/s; P =.08) and VCL (-3.25 microm/s, -3.46 microm/s; P =.2), and between MEHP with VSL (-1.09 microm/s, -2.73 microm/s; P =.1) and VCL (-0.29 microm/s, -2.93 microm/s; P =.3). In contrast to the other phthalates, MEP was positively associated with VSL and VCL but negatively associated with LIN. No consistent relationship was found for MMP and any sperm motion parameter. Although we did not find statistically significant associations, trends between CASA parameters, sperm velocity, and forward progression, and increased urinary levels of MBP, MBzP, and MEHP warrant further follow-up.

Oxidative stress in the male germ line and its role in the aetiology of male infertility and genetic disease

The human male is characterized by extremely poor semen quality as reflected in the number, morphology and motility of the spermatozoa and a high incidence of nuclear and mitochondrial DNA damage. As a consequence of these factors, defective sperm function is thought to be a major contributor to the aetiology of human infertility, as well as childhood diseases including dominant genetic mutations such as achondroplasia and cancer. Factors associated with the origin of poor semen quality include: (i) a lack of selection pressure for high fecundity genes in developed countries, (ii) an evolutionary lineage associated with the deterioration of several male fertility genes in humans and their close ancestors, (iii) genetic factors including, but not limited to, Y-chromosome deletions (iv) paternal age and (v) environmental factors. A model is proposed whereby factors such as ageing or environmental toxicants initiate DNA strand breakage in the spermatozoa of affected males, eventually leading to a mutation in the embryo. This hypothesis stresses the importance of discovering the identity of those environmental factors that are capable of damaging DNA integrity in the male germ line. Such information could make an important contribution to understanding of the origins of both male infertility and a variety of pathological conditions that affect humans, including cancer and dominant genetic disease.

Characterisation of movement pattern and velocities of stallion spermatozoa depending on donor, season and cryopreservation

The aim of the study was to compare different types of movement pattern and velocities of stallion spermatozoa depending on cryopreservation during breeding and non-breeding season. Ejaculates were collected from four stallions during May (n = 24) and December (n = 24). Parameters of sperm movement were evaluated by computer-aided sperm analysis (CASA) system, and included percentages of motile spermatozoa, different patterns of motility, the velocity, linearity (LIN), amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF). In winter the average percentages of motility were slightly higher compared to the breeding season in May (70.8 +/- 12.7% vs. 66.8 +/- 12.2%, respectively). Cryopreservation and thawing led to a significant decrease in the number of motile sperm to 11.3 +/- 5.8% in May and 15.6 +/- 7.0% in December. The pattern of motility was also changed. Detailed analysis by CASA demonstrated that cryopreservation resulted in a shift from the proportions of linear to more non-linear motile spermatozoa and to a significant increase of local motile and hyperactivated spermatozoa. Mean velocity of fresh motile spermatozoa differed between May and December (119.1 +/- 43.9 vs. 164.4 +/- 66.4 microm/sec, respectively; P < 0.05). Cryopreservation and thawing led to a slight increase of curvilinear velocity (VCL) and straight line velocity (VSL). The motility analysis has shown that the parameters BCF and ALH were highly correlated in stallion spermatozoa (r = -0.67; P < 0.001). The BCF of stallion spermatozoa was slightly reduced in the non-breeding season. Altogether, the influence of factors on the motility of stallion spermatozoa has the following rank order: cryopreservation (P < 0.0001) > stallion (P < 0.001) > season (P < 0.05).

New semen quality scores developed by principal component analysis of semen characteristics

The purpose of this study was to determine whether semen characteristics can be reduced to 2 semen quality (SQ) scores and whether these new scores can help the clinician in assessing the reproductive outcome. A cross-sectional sample of 250 patients seeking infertility treatment were analyzed for semen characteristics. In addition, 177 male-factor patients (prostatitis with infection, n = 40; varicocele, n = 77; varicocele with infections, n = 11; and vasectomy reversal, n = 43) were also assessed. Sperm motion kinetics were measured by computer-assisted semen analysis (CASA) (concentration, percent motility, curvilinear velocity [VCL], straight-line velocity [VSL], average path velocity [VAP], linearity [LIN], and amplitude of lateral head displacement [ALH]). Sperm morphology was assessed by both World Health Organization (WHO) guidelines and Tygerberg strict criteria. The principal component analysis model was used to construct an SQ score and a relative semen quality (RQ) score. A separate set of 25 normal donors was included as controls to determine normal ranges of the semen scores. Among the patient samples, SQ and RQ scores (median and 25% and 75% interquartile values) were 89.9, 25.1, and 130.4 and 106.1, 45.2, and 165.9, respectively. The SQ score for the varicocele and varicocele with infection groups was comparable (78.6 +/- 17.4 and 84.8 +/- 20.6) but significantly different from the control (100 +/- 10, P <.001 and.03). Vasectomy reversal patients had an SQ score of 78.2 plus or minus 16.8 that was significantly lower than controls (P <.001). The correlation among semen characteristics allows for the efficient combining of semen measures. The composite scores can summarize overall SQ and quantity. Both SQ and RQ scores provide meaningful information on the quality of semen specimens for the clinician.

Laurdan fluorescence: a simple method to evaluate sperm plasma membrane alterations

OBJECTIVE

To determine, by a simple fluorescence method, sperm plasma membrane alterations related with changes of lipid bilayer that, together with routine semen analysis, could help to elucidate the causes of the unexplained male infertility problems.

DESIGN

Pilot study.

SETTING

Andrology laboratory and biochemistry institute, medical school.

PATIENT(S)

Men whose semen was studied for infertility problems.

INTERVENTIONS(S)

No therapeutic intervention was performed on patients.

MAIN OUTCOME MEASURE(S)

Presence of spermatozoa plasma membrane alterations evidenced by evaluation of Laurdan fluorescence Generalized Polarization (GP) and reported as a function of increasing cell concentration, spermatozoa total motility, linear speed, and vitality.

RESULT(S)

Reporting GP values as a function of increasing sperm cell concentration, it is evident that the samples are distributed in two distinct areas: at >32 x 10(6) cells per milliliter, mean GP value was 0.303 +/- 0.015, whereas for lower sperm cell concentrations, the mean GP was 0.365 +/- 0.026 (P<.001). These data indicate that the spermatozoa plasma membranes are characterized by liquid-crystalline phases with different ordering degree and polarity and that about 50% of samples with normal semen characteristics (> or =20 x 10(6) cells per milliliter) show high GP values.

CONCLUSION(S)

Laurdan fluorescence can be used as a simple method to evaluate spermatozoa plasma membrane alterations, particularly in a group of infertile men presenting normal semen parameters. In these samples, Laurdan could be used as a simple tool for infertility assessment. In fact, it is known that compositional and physicochemical alterations of bilayer features can be important for the fertilizing ability of spermatozoa because they are necessary for a proper physiological membrane activity.

Molecular evaluation of two major human sperm fibrous sheath proteins, pro-hAKAP82 and hAKAP82, in stump tail sperm

OBJECTIVE

To determine whether mutations in the pro-hAKAP82 gene and the resulting pro-hAKAP82 and hAKAP82 proteins were associated with the infertility seen in a patient with stump tail sperm.

DESIGN

Case report.

SETTING

Academic research and teaching environment, tertiary care hospital.

PATIENT(S)

A single, infertile Caucasian male diagnosed with essentially 100% stump tail sperm.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Electrophoresis, silver staining, and immunoblotting of patient and control sperm proteins; RII (type II regulatory subunit of protein kinase-A) overlay assay of patient and control sperm proteins, partial DNA sequence analysis of patient's pro-hAKAP82 gene; indirect immunofluorescence and immunogold electron microscopy of patient and control sperm.

RESULTS(S)

No significant abnormalities in the size or amount of pro-hAKAP82 and hAKAP82 or in the ability of these proteins to bind the regulatory subunit of protein kinase-A were identified in the patient's sperm. Partial sequence analysis of the patient's pro-hAKAP82 gene was identical to the published normal sequence. Indirect immunofluorescence and immunoelectron microscopy of sperm localized pro-hAKAP82/hAKAP82 to the sperm flagellum and demonstrated that the proteins were present in a disorganized, amorphous region, which apparently represented the fibrous sheath.

CONCLUSION(S)

These results suggest that, although pro-hAKAP82 and hAKAP82 localize to the correct structural component of the flagellum and are not directly responsible for the stump tail phenotype, they are unable to assemble normally into the fibrous sheath. Although this study did not identify abnormalities in the pro-hAKAP82 gene or its resulting proteins in a patient with stump tail sperm, several regions of the gene and protein remain to be examined.

[Predictive value of non-automated spermatic parameters and automated kinetic parameters on cleavage rate in fertilization in vitro]

The aim of this work was to determine retrospectively in 114 couples the predictive value of semen analysis for the in vitro fertilization (IVF) outcome when sperm evaluation before IVF was assessed by either conventional parameters or a Hamilton-Thorne automated motility analyser. A backward logistic regression analysis was used to study the relative contribution of each conventional or computerized parameter. Computerized sperm values were the worst index for predicting oocyte fertilization. However a tight relationship between morphology and cleavage ratio was observed. Using ROC analysis, under a 18% threshold, cleavage failure was noted in 71% of couples undergoing an IVF program. This study indicates that morphology is the best parameter for predicting cleavage failure.

Immunoreactive relaxin in seminal plasma of fertile boars and its correlation with sperm motility characteristics determined by computer-assisted digital image analysis

Ejaculates from 10 mature fertile large white Yorkshire boars were used to examine the correlation between immunoreactive relaxin levels in seminal plasma and sperm motility characteristics. Seminal plasma levels of immunoreactive relaxin were measured by a time-resolved fluoroimmunoassay (TR-FIA). Motility characteristics were assessed using a CellSoft computer-assisted digital image analysis system. The mean +/- SD level of immunoreactive relaxin in seminal plasma was 2.61 +/- 0.62 ng/mL. When the correlation between seminal plasma levels of immunoreactive relaxin and parameters of sperm movement was examined, it was found that relaxin levels were significantly correlated with the percentage of motile spermatozoa (r=0.687, p < 0.05), curvilinear velocity (r=0.745, p < 0.05), straight line velocity (r=0.651, p < 0.05), mean amplitude of lateral head displacement (mean ALH) (r=0.844, p < 0.01) and the maximum amplitude of lateral head displacement (max ALH) (r=0.830, p < 0.01), but not with linearity, beat-cross frequency, or percentage of circular cells. Among these parameters, seminal plasma levels of immunoreactive relaxin showed the strongest correlation with the ALH parameter related to fertilizing ability. These results indicate that immunoreactive relaxin in boar semen may be necessary not only for normal sperm motility but also for normal fertility, suggesting that determination of the profile of immunoreactive relaxin in ejaculates may have value as a potential marker for predicting sperm fertilizing ability of boars.

Relationship between sperm motility and the processing and tyrosine phosphorylation of two human sperm fibrous sheath proteins, pro-hAKAP82 and hAKAP82

Sperm motility is regulated by the cAMP-dependent protein kinase (protein kinase-A)-mediated phosphorylation of a group of largely unidentified flagellar proteins. Human AKAP82 (hAKAP82) and its precursor protein, pro-hAKAP82, are members of the A-kinase anchor protein (AKAP) family. These proteins tether protein kinase-A to the fibrous sheath of human spermatozoa and presumably localize the activity of the kinase near specific targets in the sperm flagellum. In this way, pro-hAKAP82 and hAKAP82 may be involved in regulating sperm motility. Similar to its homologues in other species, pro-hAKAP82 is proteolytically processed to hAKAP82. However, the amount of processing of pro-hAKAP82 in human spermatozoa is less than the amount of processing of the precursor in other species. We postulated that this lower extent of processing may be related to lower percentages of human sperm motility. In addition, both pro-hAKAP82 and hAKAP82 are tyrosine phosphorylated in a capacitation-dependent manner. Since capacitation is associated with hyperactivated motility, we postulated that tyrosine phosphorylation of pro-hAKAP82/hAKAP82 is associated with changes in motility. However, using a combination of immunofluorescence and immunoblotting approaches, we found no evidence for an association between either processing or tyrosine phosphorylation of pro-hAKAP82/hAKAP82 and significant differences in motility in spermatozoa from normal men.

Application of the upgraded image superimposition system (SIAS) to the assessment of sperm kinematics

Dedicated software for semiautomatic objective motility assessment, based on image superimposition (SIAS), was upgraded in order to allow automatic reading of sperm tracks whilst keeping the advantages of visual check instead of the digital images of classic computer-aided sperm analysis (CASA) systems. The new system is very fast and accurate and allows an excellent reading of sperm motility in standard semen analysis. Moreover, using this system, an attempt was made to define numerically straight-line velocity (VSL), curvilinear velocity (VCL) and linearity (LIN) in each WHO sperm motility class. At 21 frames sec-1, ROC curves analysis determined the following: Class 1 (typical of WHO grade 'a'): VSL > or = 23 microns sec-1 and LIN > or = 0.58; class 2 (typical of WHO grade 'b'): VSL > 10 and < 23 microns sec-1 and LIN > or = 0.58; class 3: VSL > 10 microns sec-1 and LIN < 0.58 (this additional class was added to differentiate nonstraight progressive motility from classes 1 and 2); class 4 (typical of WHO grade 'c'): VSL < or = 10 microns sec-1. The numerical definition of sperm motility classes may contribute towards standardization in the objective evaluation of sperm kinematics.

Are sperm motion parameters influenced by varicocele ligation?

OBJECTIVE

To document objectively, improvements in sperm motion parameters in subfertile men after varicocele ligation with the use of computer-aided sperm analysis.

DESIGN

Retrospective chart review.

SETTING

An academic clinical environment.

PATIENT(S)

Thirty-four men with varicocele as the primary cause of infertility who underwent a physical examination, hormonal profile, and Doppler ultrasound evaluation.

INTERVENTION(S)

Computer-aided sperm analysis was performed before and after either subinguinal or laparoscopic varicocele ligation.

MAIN OUTCOME MEASURE(S)

Patients were followed up for 3-18 months after operation, and average computer-aided sperm analysis values were obtained before and after operation. Computer-aided sperm analysis values were analyzed by paired Student's t-test, with special reference to motility and sperm motion parameters.

RESULT(S)

After varicocele ligation, patients demonstrated increases in mean sperm density and in the overall distribution of sperm with rapid velocity, although the increases were not statistically significant. Mean measures of straightness, linearity, and track speed also were increased after operation, but only progressive sperm velocity was increased to a statistically significant level.

CONCLUSION(S)

Because progressive velocity has been a primary computer-aided sperm analysis parameter predictive of male fertility and the success of assisted reproductive techniques, we conclude that varicocele ligation results in improvements in semen parameters, especially the key parameter of progressive sperm velocity.

Papanicolaou and Kruger assessment of sperm morphology: thresholds and agreement

The current World Health Organization guidelines (1992) suggest that the presence of > or = 30% normal sperm forms (i.e. PAP criteria) is consistent with normal semen quality. Critical evaluation of sperm morphology (CE; Kruger classification) has shown an excellent correlation with human in vitro fertilization. Utilizing Kruger criteria, > 14% normal sperm forms has been proposed as indicative of normal semen quality. We have performed a retrospective analysis on 261 individuals to assess the agreement between PAP and Kruger criteria for normal sperm morphology (NSM). When the threshold for NSM by PAP was set at 30%, a significant agreement was found between the percentage normal forms of both criteria (Kappa coefficient = 0.37; p < 0.001). Sixty-seven (92%) of the 73 men found to have abnormal sperm morphology by PAP had abnormal semen by Kruger classification. When the threshold for NSM by PAP was established at 50%, the Kappa coefficient was 0.48 (p < 0.001). Sixty of the 72 samples (83%) classified as normal by PAP staining were normal by Kruger criteria. Interestingly, when NSM by PAP was between 30 and 50%, the specimen was just as likely to have normal or abnormal sperm morphology by Kruger (40 vs. 60%, respectively). These results strongly suggest that a high or low percentage of NSM by PAP is in agreement with the Kruger classification. The excellent agreement of Kruger and WHO criteria at the extremes (< 30% and > 50%) may obviate the need for Kruger assessment. However, when WHO morphology is between 30 and 50%, the addition of Kruger evaluation may provide meaningful information to help better diagnose a patient and plan his treatment.

New system for long-term monitoring of sperm motility: EDTA effect on semen

Many drugs act as sperm stimulants and are of clinical value for male infertility. Current research deals with the physiological mechanisms of sperm motility/sperm stimulation and how long the effect lasts. For such a study, long-term monitoring of sperm motility becomes essential for traditional semen evaluation. A new system was designed to deal with the microscopic images of semen. Its performance was evaluated by studying the effect of EDTA on sperm motility. EDTA increased sperm curvilinear velocity (Vcl) and straight-line velocity (Vsl) by 31 and 20%. EDTA also prolonged the duration of motility by 68 and 61%, respectively. However, EDTA had less effect on the linearity of forward progression (Lin). The proposed system can analyze semen and does well at monitoring sperm motility for short term and long term. It may be valuable to test the possible role of sperm stimulation for male infertility and assisted reproduction.

Human sperm morphology and in vitro fertilization: sperm tail defects are prognostic for fertilization failure

The aim of this study was to determine the relationship between sperm morphology and fertilization rates in vitro. Semen samples were obtained from 50 couples undergoing IVF treatment. Sperm morphology was classified by strict criteria (Tygerberg) according to head, midpiece and tail defects in neat semen and after sperm selection by Percoll gradient centrifugation. Percoll preparation significantly increased the percentage of sperm with normal morphology from 13 to 20%. However, the greatest single regression coefficient was observed with the percentage of sperm with tail defects and correlated negatively with fertilization rates in vitro both before and after Percoll preparation. Therefore, tail morphology may be of value as a prognostic factor in assisted conception both before and after Percoll preparation.

Assessment of hyperactivation, acrosome reaction and motility characteristics of spermatozoa from semen of men of proven fertility and unexplained infertility

Semen from men of proven fertility was compared with that of men with unexplained infertility to determine differences in spermatozoal functions such as hyperactivation and acrosome reaction and spermatozoal motility characteristics. The hyperactivated spermatozoa in both groups could be visualised on the monitor of the Computer Assisted Semen Analyser and they exhibited 'circling', 'thrashing', 'starspin' and 'helical' motility patterns and the mean hyperactivation rates were not significantly different. However, 20% of the men with unexplained infertility did not exhibit hyperactivation compared to only 4% in the fertile group. Furthermore, the semen from infertile men when evaluated for hyperactivation could be categorised into two groups with those having lower hyperactivation (< 10% or < 6% after 4 and 6 h of incubation respectively), forming the first group, and those having a higher hyperactivation rate constituting the second group. In the fertile men such distinct groups were not visible and the percentage hyperactivation ranged from 1 to 16%. No significant differences were observed in the rate of acrosome reaction of fertile and unexplained infertile men. The non-hyperactivated spermatozoa from unexplained infertile men showed a significant increase in path velocity (VAP), curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH) and a decrease in linearity (LIN) and straightness (STR) compared to spermatozoa from fertile men. Furthermore, the hyperactivated spermatozoa from infertile men also showed an increase in progressive velocity (VSL) (only after 2 h of incubation) and LIN and decrease in ALH and beat cross frequency (BCF) compared to spermatozoa from fertile men. The results are discussed in the light of the importance of the above spermatozoal functions and spermatozoal parameters in fertilization.

The predictive value of the sperm-cervical mucus interaction test on the outcome of in vitro fertilization and ovulation induction combined with intrauterine insemination

We investigated the effect of the sperm-cervical mucus penetration tests (SPT) on the fertilization rate (FR) and pregnancy rate (PR) in patients treated with either in vitro fertilization (IVF) or ovulation induction combined with intrauterine insemination (OI + IUI). Infertile couples where the women had normal ovarian function and a normal pelvis at laparoscopy and her partner had normal seminology who had failed at least 2 SPTs were treated with either IVF or OI + IUI. These patients were compared with similar couples in whom SPTs were satisfactory (SPT/ve). Group A (SPT+ve) consisted of 46 patients who underwent 78 treatment cycles of IVF and Group B (SPT-ve) comprised 31 patients who underwent 35 IVF cycles. Group C (SPT/ve) consisted of 39 patients who underwent 84 treatment cycles with OI + IUI, and Group D (SPT-ve) consisted of 15 patients who underwent 37 cycles with the same treatment. In patients treated with IVF, the FR and PR per embryo transfer were 77.0% and 20.0% respectively in Group A, and 64.0% and 22.6% respectively in Group B. The difference in FRs was statistically significant (p > 0.001) but there was no difference in the PRs. In patients treated with OI + IUI, the PR per cycle were 22.0% in Group C and 16.2% in Group D. These results indicate that SPT failure was associated with a lower FR in IVF but this did not affect the PRs. Similarly there was no difference in PRs following OI + IUI.

Peritoneal fluid from women with moderate or severe endometriosis inhibits sperm motility: the role of seminal fluid components

OBJECTIVE

To examine the mechanism of sperm motility inhibition by peritoneal fluid (PF) from women with endometriosis.

DESIGN

Prospective, randomized study.

SETTING

University-based andrology laboratory.

PATIENTS

Women with and without endometriosis.

INTERVENTIONS

Fresh semen or Percoll-purified sperm fractions were combined with PF from women with endometriosis (n = 20), from fertile women without endometriosis (n = 10), or with physiological saline.

MAIN OUTCOME MEASURE

Sperm motility parameters were determined with computer assisted semen analysis. Data were evaluated by the analysis of variance and the Student's t-test.

RESULTS

Peritoneal fluid from women with minimal or mild endometriosis did not inhibit sperm motility in semen. Peritoneal fluid from women with moderate or severe endometriosis caused approximately 40%, 50%, and 80% declines in sperm motility and in percent progressive motile sperm after 4,7, and 24 hours, respectively. Sperm velocity was inhibited by approximately 30% and 60% after 7 and 24 hours, respectively. However, in the Percoll-purified sperm fractions the same PF did not inhibit sperm motility within the 4- to 7-hour time frame, and only a 17% to 42% inhibition occurred after the overnight incubation. Sperm velocity was not affected.

CONCLUSION

Cellular components of seminal fluid appear to mediate the inhibitory action of PF. Assuming that the leukocyte components of semen and PF are common, the cell-mediated inhibition of sperm motility is a likely contributor to endometriosis related infertility.

The effect of sperm-mucus interaction test on the outcome of in vitro fertilization and ovulation induction combined with intrauterin insemination

OBJECTIVE

To investigate the effect of sperm mucus penetration tests (SPT) on the fertilization rate (FR) and pregnancy rate (PR) in patients treated with either in vitro fertilization (IVF) or ovulation induction combined with intrauterine insemination (OI + IUI).

METHODS

Retrospective analysis of a regional Infertility Unit database. Infertile couples where the women had normal ovarian function and a normal pelvis at laparoscopy and her partner had normal seminology who had failed at least two SPTs who were treated with either IVF or OI + IUI. These patients were compared with similar couples in whom SPTs were satisfactory (SPT + ve). Group A (SPT + ve) consisted of 46 patients who underwent 78 treatment cycles of IVF and Group B (SPT - ve) comprised 31 patients who underwent 35 IVF cycles. Group C (SPT + ve) consisted of 39 patients who underwent 84 treatment cycles with OI + IUI, and Group D (SPT - ve) consisted of 15 patients who underwent 37 cycles with the same treatment.

RESULTS

In patients treated with IVF, the FR and PR per embryo transfer were 77.0% and 20.0%, respectively in Group A, and 64.0% and 22.6%, respectively in Group B. The differences in FRs were statistically significant (p < 0.001) but there was no difference in the PRs. In patients treated with OI + IUI, the PR per cycle were 22.0% in Group C and 16.2% in Group D.

CONCLUSION

The results indicate that SPT failure was associated with a lower FR in IVF but this did not affect the PRs. Similarly there was no difference in PRs following OI + IUI.

The effect of peritoneal fluid from patients with endometriosis on human sperm function in vitro

OBJECTIVE

Our purpose was to evaluate the effect of peritoneal fluid from women with endometriosis on sperm motility and function in an in vitro model.

STUDY DESIGN

Peritoneal fluid was collected at laparoscopy from patients with and without endometriosis. Human donor sperm was diluted with this fluid, and its effect on sperm function and motility was measured was measured with the zona-free hamster egg sperm penetration assay and computer-assisted semen analysis.

RESULTS

The mean number of eggs penetrated by the sperm mixed with peritoneal fluid from patients with endometriosis was significantly fewer than the number penetrated by the sperm mixed with fluid from control patients (22.9 +/- 5.31 vs 44.4 +/- 4.96, p < 0.01, Student t test, n = 20). When evaluated by computer-assisted semen analysis, sperm mixed with peritoneal fluid from patients with endometriosis showed a significant decrease in mean swimming velocity compared with sperm mixed with peritoneal fluid from control patients (54.0 +/- 1.77 vs 59.2 +/- 1.05, p = 0.02, Student t test, n = 20). A significant increase in the fraction of sperm swimming at slower velocities was also found. A trend toward a positive correlation between eggs penetrated and sperm velocity was seen, but statistical significance was not achieved (correlation coefficient 0.4392, p = 0.053, n = 20).

CONCLUSION

These data suggest that substances found in the peritoneal fluid of patients with endometriosis could contribute to infertility through impairment of both sperm function and motion kinematics.

There is no relationship between concentration, motility and vacuolated cells

To determine whether there are differences between concentration and motility in the vacuolated spermatozoa of fertile donors, randomized men and infertile patients, semen samples were compared. Based on the percentages of concentration and motility, samples were divided into three groups: Group I, fertile donors, concentration > 20 x 10(6)/ml, motility > 50%; Group II, patients, concentrations < 20 x 10(6)/ml, motility < 50%; Group III, randomized men, concentration > 20 x 10(6)/ml, motility > 50%. In each group samples were assessed morphologically by the strict criteria of Kruger et al. The results showed that there was no difference between Group I and Group II, but there were differences between Group III and Group II, and Group III and Group I. We conclude that there is no relationship between concentration, motility and vacuolated cells.

Intracytoplasmic sperm injection and conventional in vitro fertilization for sibling oocytes in cases of unexplained infertility and borderline semen

PURPOSE

In a prospective study, conventional IVF and intracytoplasmic sperm injection (ICSI) were performed on sibling oocytes of 22 patients with unexplained infertility (Group A) and 24 patients with borderline semen (Group B).

RESULTS

In Group A, there was no significant difference (P = 0.070) in the fertilization rate per oocyte between ICSI (63%) and conventional IVF (50.7%), however, there was total failure of fertilization in conventional IVF in 5 of the 22 patients with IVF and none in ICSI. In group B, there was a significant difference (P < 0.001) between the fertilization rate per oocyte in ICSI (59%) and conventional IVF (27.1%). There was total failure of fertilization in 11 patients after conventional IVF and none after ICSI.

CONCLUSIONS

The study showed that 22.7% of unexplained infertility and 45.8% of patients with borderline semen would have lost their chance of embryo transfer completely because of total failure of fertilization if ICSI was not performed on some oocytes in this cycle.

Characterization of zebra mussel (Dreissena polymorpha) sperm morphology and their motility prior to and after spawning

In order to understand more about the reproductive physiology of the zebra mussel (Dreissena polymorpha), we have examined the effect of spawning on the kinematics and fertilization ability of their spermatozoa. Sperm morphology was characterized using scanning electron microscopy, differences in sperm kinematics were examined using CASA following manual collection of sperm from the gonad or spawning induced by 5-hydroxytryptamine (5-HT), and the fertilization ability of spawned and manually removed spermatozoa were compared. D. polymorpha sperm have a tail 50 microns long, a midpiece consisting of four spherical mitochondria-rich regions approximately 0.6 micron in diameter, a conical nucleus 2.52 microns in length, and a cylindrical acrosome 0.72 micron in height and width. Kinematic analysis revealed that manually removed sperm exhibit significantly lower motion characteristics as compared to spawned sperm. Treatment with 5-HT had no significant effect on the sperm kinematics of either manually removed or spawned spermatozoa. These data suggest that D. polymorpha spermatozoa have a similar morphology to other bivalve sperm, spawning results in a significant enhancement in sperm kinematics, and 5-HT does not directly alter sperm motion.