Assessment of sperm motion characteristics from fertile and infertile men using a fully automated computer-assisted semen analyzer

Semen evaluation: methodological advancements in sperm quality-specific fertility assessment - A review

Assessment of male fertility is based on the evaluation of sperm. Semen evaluation measures various sperm quality parameters as fertility indicators. However, semen evaluation has limitations, and it requires the advancement and application of strict quality control methods to interpret the results. This article reviews the recent advances in evaluating various sperm-specific quality characteristics and methodologies, with the help of different assays to assess sperm-fertility status. Sperm evaluation methods that include conventional microscopic methods, computer-assisted sperm analyzers (CASA), and flow cytometric analysis, provide precise information related to sperm morphology and function. Moreover, profiling fertility-related biomarkers in sperm or seminal plasma can be helpful in predicting fertility. Identification of different sperm proteins and diagnosis of DNA damage has positively contributed to the existing pool of knowledge about sperm physiology and molecular anomalies associated with different infertility issues in males. Advances in methods and sperm-specific evaluation has subsequently resulted in a better understanding of sperm biology that has improved the diagnosis and clinical management of male factor infertility. Accurate sperm evaluation is of paramount importance in the application of artificial insemination and assisted reproductive technology. However, no single test can precisely determine fertility; the selection of an appropriate test or a set of tests and parameters is required to accurately determine the fertility of specific animal species. Therefore, a need to further calibrate the CASA and advance the gene expression tests is recommended for faster and field-level applications.

A collective tracking method for preliminary sperm analysis

Background

Total motile sperm count (TMSC) and curvilinear velocity (VCL) are two important parameters in preliminary semen analysis for male infertility. Traditionally, both parameters are evaluated manually by embryologists or automatically using an expensive computer-assisted sperm analysis (CASA) instrument. The latter applies a point-tracking method using an image processing technique to detect, recognize and classify each of the target objects, individually, which is complicated. However, as semen is dense, manual counting is exhausting while CASA suffers from severe overlapping and heavy computation.

Methods

We proposed a simple frame-differencing method that tracks motile sperms collectively and treats their overlapping with a statistical occupation probability without heavy computation. The proposed method leads to an overall image of all of the differential footprint trajectories (DFTs) of all motile sperms and thus the overall area of the DFTs in a real-time manner. Accordingly, a theoretical DFT model was also developed to formulate the overall DFT area of a group of moving beads as a function of time as well as the total number and average speed of the beads. Then, using the least square fitting method, we obtained the optimal values of the TMSC and the average VCL that yielded the best fit for the theoretical DFT area to the measured DFT area.

Results

The proposed method was used to evaluate the TMSC and the VCL of 20 semen samples. The maximum TMSC evaluated using the method is more than 980 sperms per video frame. The Pearson correlation coefficient (PCC) between the two series of TMSC obtained using the method and the CASA instrument is 0.946. The PCC between the two series of VCL obtained using the method and CASA is 0.771. As a consequence, the proposed method is as accurate as the CASA method in TMSC and VCL evaluations.

Conclusion

In comparison with the individual point-tracking techniques, the collective DFT tracking method is relatively simple in computation without complicated image processing. Therefore, incorporating the proposed method into a cell phone equipped with a microscopic lens can facilitate the design of a simple sperm analyzer for clinical or household use without advance dilution.

Porcine seminal protein-I and II mRNA expression in boar spermatozoa is significantly correlated with fertility

In recent years, genomic and proteomic biomarkers have been identified for the diagnosis of male fertility to overcome the limitations of conventional semen analysis. Owing to the limited genes available so far, the single gene approach is commonly adopted for analyzing the phenotype of interest. However, the single-gene approach is less effective than multiple-gene strategies for diagnosing a desirable phenotype. Herein, we investigate the ability of two fertility-related genomic markers (porcine seminal protein (PSP)-I and PSP-II) in spermatozoa to predict boar litter size in addition to conventional semen parameters. First, we examined different semen parameters (motility, motion kinematics, and capacitation status) and gene expression in high- and low-litter size boar spermatozoa. Then, we evaluated the correlation of these parameters with the fertility of 21 Yorkshire boars. Finally, we investigated the efficacy of single/combined markers to predict male fertility using a comprehensive statistical model. Our result showed that there were no significant differences in sperm motility, motion kinematics, or capacitation status, however, the mRNA expression of PSP-I and PSP-II in spermatozoa was significantly different in high- and low-litter size boars. In the individual screening test, the expression of both genes was negatively correlated with boar fertility (r = 0-0.578 and -0.456, respectively), whereas only hyperactivation (HYP) showed a positive correlation (r = 0.444) among the tested semen parameters. As single markers, PSP-I and PSP-II have a better diagnostic power to predict boar fertility, regardless of HYP, in quality assessment analyses. In addition, when these markers were combined, the positive predictive value, negative predictive value, and overall test effectiveness for fertility detection were improved. Surprisingly, when PSP-I and PSP-II were considered together, the deviation of the predicted average litter size between high- and low-litter size boars was 1.77. Based on the findings, we suggest that the use of genomic markers in spermatozoa rather than commonly analyzed semen parameters may be more accurate for evaluating male fertility. Moreover, using a combination of markers could increase the overall accuracy of (in)fertility predictions, and thus, could be considered for field application.

Impact of kudzu and puerarin on sperm function

The goal of this study was to investigate the impact of kudzu (Pueraria mirifica) and the isoflavone puerarin in functional toxicological tests on spermatozoa and to assess the affinity of extracts and pure isoflavones for estrogen receptor (ER)-alpha and -beta (ERα, ERβ) in receptor binding assays. Capacitation, acrosome reaction and chromatin decondensation in spermatozoa were analyzed using microscopic analysis. Kudzu, but not puerarin, reduced motility of sperm. Puerarin reduced the percent spontaneous acrosome reaction in spermatozoa. The pathways used by kudzu that affect sperm function are not fully mirrored by puerarin. Puerarin, kudzu and its other phytoestrogenic components displayed preferential affinity for ERβ, however the diverse effects of kudzu and puerarin on sperm function implicate the involvement of multiple signaling systems.

Ram Sperm Motility Parameters under The Influence of Epidermal Growth Factor

Epidermal growth factor (EGF) is one of the important cytokines that play a role in fertility. It is known that EGF affects both male and female reproduction, but its effect on sperm parameters is not fully understood. Up to the present, the effect of EGF on ram sperm motility parameters has not been published. We analyzed motility parameters of ejaculates after 24, 48, and 72 hours from the EGF addition. EGF was added to chilled ram sperm at concentrations of 0, 100, 200, and 400 ng·ml⁻¹. Analyses were realized using computer, assisted semen analyzer (CASA)—Hamilton Thorn motility analyzer (version 7). The effect of EGF was already visible after 30 min of incubation. Significant effect on ram sperm total motility and progressive movement was observed at higher EGF concentrations after 48 h of incubation. Our results show that EGF affects sperm motility parameters depending on concentration and time of exposure.

Effect of semen preparation on casa motility results in cryopreserved bull spermatozoa

Computer-assisted sperm analyzers (CASA) have become the standard tool for evaluating sperm motility and kinetic patterns because they provide objective data for thousands of sperm tracks. However, these devices are not ready-to-use and standardization of analytical practices is a fundamental requirement. In this study, we evaluated the effects of some settings, such as frame rate and frames per field, chamber and time of analysis, and samples preparations, including thawing temperature, sperm sample concentration, and media used for dilution, on the kinetic results of bovine frozen-thawed semen using a CASA. In Experiment 1, the frame rate (30-60 frame/s) significantly affected motility parameters, whereas the number of frames per field (30 or 45) did not seem to affect sperm kinetics. In Experiment 2, the thawing protocol affects sperm motility and kinetic parameters. Sperm sample concentration significantly limited the opportunity to perform the analysis and the kinetic results. A concentration of 100 and 50 x 10(6) sperm/mL limited the device's ability to perform the analysis or gave wrong results, whereas 5, 10, 20, and 30 x 10(6) sperm/mL concentrations allowed the analysis to be performed, but with different results (Experiment 3). The medium used for the dilution of the sample, which is fundamental for a correct sperm head detection, affects sperm motility results (Experiment 4). In this study, Makler and Leja chambers were used to perform the semen analysis with CASA devices. The chamber used significantly affected motility results (Experiment 5). The time between chamber loading and analysis affected sperm velocities, regardless of chamber used. Based on results recorded in this study, we propose that the CASA evaluation of motility of bovine frozen-thawed semen using Hamilton-Thorne IVOS 12.3 should be performed using a frame rate of 60 frame/s and 30 frames per field. Semen should be diluted at least at 20 x 10(6) sperm/mL using PBS. Furthermore, it is necessary to consider the type of chamber used and perform the analysis within 1 or 2 min, regardless of the chamber used.

Assessment of fertility by sperm mechanical energy using computer-assisted sperm analysis system

Purpose

It is known that the energy distribution of sperm obeys the following equations and the total mechanical energy in a sperm population is expressed as nKλ × a constant. nKλ/10² is defined as the sperm energy index (SEI). [Formula: see text] Here, P is the existing probability density of sperm, t is the square of amplitude of lateral head displacement, λ is the mean of t, n is the number of motile sperm in semen in a measurement field, and K is a constant determined for each semen sample. These values can be obtained with the use of computer-assisted sperm analysis (CASA).

Methods

Sperm motility parameters were measured using CASA in 163 ejaculated semen samples from 47 infertile men (infertility group), and 162 ejaculated semen samples from 45 fertile men (natural pregnancy group). Kλ is defined for the present investigation as the mean energy index (MEI). SEI and MEI were obtained according to the methods described in sperm energy theory.

Results

There were no natural pregnancy subjects with SEI < 0.5. All subjects with MEI > 2.0 and SEI > 1.0 were in the natural pregnancy group.

Conclusions

An assessment of fertility was possible by using the sperm energy index.

Comparison of Computer-assisted Sperm Motility Analysis Parameters in Semen from Belgian Blue and Holstein?Friesian Bulls

Subjective microscopic sperm motility results have recently been demonstrated to differ between Holstein-Friesian (HF) and Belgian Blue (BB) bulls. However, such assessments are rather imprecise. In the present study, sperm motility was assessed objectively by means of the Hamilton Thorne CEROS version 12.2c computer-assisted sperm motility analyser (CASA), and differences between the BB and HF breed could also be demonstrated. Higher percentages of both totally (p < 0.0001) and progressively (p < 0.0001) motile spermatozoa were encountered in the HF breed compared with the BB breed. Furthermore, a lower kinetic efficiency of the BB spermatozoa, evidenced by a lower beat cross-frequency (p = 0.0007) combined with a higher lateral head displacement (p = 0.0015), was the basis for the lower velocity of BB sperm cells. Additionally, BB spermatozoa move less straight forward, resulting in a lower straightness (p < 0.0001). No sperm motility differences were observed between age groups within the BB breed. The breed differences were observed in the examined bull populations residing at AI centres, in Belgium for the BB bulls and in the Netherlands for the HF bulls. However, these bull populations are selected for fertility. A similar pattern was observed in an unselected bull population of both breeds, although these differences were mostly non-significant for the different CASA parameters. Nevertheless, these data suggest that a genetic component might be responsible for the observed sperm motility breed differences.

Comparison of sperm quality of Belgian Blue and Holstein Friesian bulls

Few data are currently available on sperm quality of Belgian Blue (BB) bulls. The present study compared sperm quality of BB to Holstein Friesian (HF) bulls of several age categories, by means of a classical semen evaluation. Volume and concentration, and consequently total sperm output depended largely on age. Gross, total, and progressive motility, % live and % normal spermatozoa were significantly lower in the BB breed. Primary sperm abnormalities, such as nuclear vacuoles, midpiece defects and cytoplasmic droplets which were noticed most frequently, occurred far more in the BB breed. Hence, disturbances in spermiogenesis are deemed to be the cause of the poorer BB sperm quality. Since these sperm abnormalities occur significantly more in the BB breed than in the HF breed, it seems as if the BB breed is genetically predisposed to a higher susceptibility to environmental stresses which are known to interfere with normal spermiogenesis. The small scrota typical of the inbred BB breed might in part be responsible for this, and therefore selection for larger scrota in the BB breed is advisable.

Validation and Usefulness of the Sperm Quality Analyzer (SQA II-C) for Bull Semen Analysis

In this study, an upgrade version of the Sperm Quality Analyzer (SQA), the SQA-IIC was tested for the assessment of bull semen quality. In Expt 1, the device showed good repeatability of measurements within and between capillaries, as evidenced by the low coefficients of variation (CVs; < 13%) at concentrations between 35 and 705 x 10(6) spermatozoa/ml. In Expt 2, 10 semen concentrations (1-1000 x 10(6)/ml) were stored in HEPES TALP for 48 h at room temperature. A time-dependent decrease in sperm motility index (SMI) values was noticed. SMI values increased linearly with increasing sperm concentrations, but remained constant around 500, corresponding to a concentration of approximately 50 x 10(6)/ml. For sperm concentrations below 50 x 10(6)/ml, SMI values were highly correlated with concentration (p < 0.05) and with semen parameters, expressing the overall semen quality (p < 0.05; Expt 3). In Expt 4, a correlation of only 0.44 (p < 0.05) between SMI values of frozen-thawed semen samples of 35 bulls and the corrected 56-day non-return rate (56dNRRc) was found. Prediction of the 56dNRRc based on the SMI value of a semen sample was inaccurate. The present study indicates that the SQA-IIC is suitable for a rapid screening of bull semen diluted to a concentration of approximately 50 x 10(6)/ml. Furthermore, the device seems inappropriate for fertility prediction.

Effect of technical settings on canine semen motility parameters measured by the Hamilton-Thorne analyzer

Computerized measuring devices are needed to assess canine semen quality objectively both for research and practical purposes. As internal image settings may influence the results considerably, the effect of different technical settings and semen processing on the parameters assessed by the Hamilton-Thorne Ceros 12.1 semen analyzer (HTR Ceros 12.1) was investigated. The frame rate (15, 30 or 60 frames/s) significantly (P<0.05) influenced most of the measured motility characteristics in experiment 1 while no differences in the motility parameters were found using a different sampling duration (0.5 or 1 s, i.e. 30 or 60 frames scanned) in experiment 2. In experiment 3, an increase in sperm velocity (VAP, VSL, VCL), in linearity and in the percentage of motile and rapidly moving spermatozoa was observed with increasing sperm concentrations (25 x 10(6), 50 x 10(6) or 100 x 10(6) ml(-1)). In experiment 4, a clear effect of the diluent used was visible with higher velocity parameters (VAP, VSL, VCL) and higher percentages of motile, progressive and rapid spermatozoa for semen samples diluted in Hepes-TALP or prostatic fluid in comparison with physiological saline or egg-yolk-Tris extender. In experiment 5, significant (P<0.01) and high correlations were found between the conventional dog semen analysis methods and HTR Ceros 12.1 measurements (n=97 semen samples) for the sperm concentration (r=0.91), the motility (r=0.74) and the progressive motility (r=0.84). In experiment 6, the ejaculates from 21 proven, fertile dogs were compared with the ejaculates of a population (N: 11) of young beagles (1.5 years) but no significant differences in HTR Ceros 12.1 measurements were found between the two groups. Based on our results, diluting dog semen samples to 50 x 10(6) ml(-1) with physiological saline solution and scanning 30 frames at a frame rate of 60 frames/s (i.e. a scanning time of 0.5 s), are the set-up parameters proposed to obtain objective and standardized canine semen motility results using the HTR Ceros 12.1.

Use of a new computerized system for evaluation of spermatozoal motility and velocity characteristics in relation to fertility levels in dromedary bulls

Three ejaculates from each of 14 dromedary bulls were collected at 7-day intervals and diluted to 50 x 10 (6) spermatozoa per ml with sodium citrate (2.9%) seminal extender. Spermatozoal concentrations, motility percentages and velocity measures were evaluated by a new computerized cell motion analyzer (CMA, medical Technologies Montreux SA, Switzerland) for assessing fertility rates in such animals. Greatest variability in concentrations and motility percentages was generally attributed to animal effect within the first ejaculate. Spermatozoal concentrations and kinematic variables in particular percentages of progressive motility, amplitude of lateral head displacement (ALH) and linearity (LIN) percentage were strongly correlated (P<0.01) with fertility rates of dromedary bulls. The CMA-derived measurements of velocity straight line (VSL), velocity curve line (VCL), and velocity averaged line (VAP) were significantly affected by the type of spermatozoal tracks. The present results evidenced that the CMA is a reliable system for determining spermatozoal concentrations, motility percentages and velocity measures and is considered as an accurate and rapid method for evaluating and predicting fertility in the one-humped camel bulls.

Evaluation of the "Hamilton Thorn computer-based automated system" for dog semen analysis

An objective evaluation of semen is warranted to assess the canine male fertility and to select appropriate techniques and extenders for semen preservation. With conventional microscopic evaluation, the subjectivity of the analysis makes any comparison of results difficult. In the present study, we validated the Hamilton Thorn computer-aided semen analyzer (HTR-IVOS10 analyzer) for objective assessment of canine semen. A description of fertile canine motility parameters using this analyzer is reported. Semen analysis at 38 degreesC is found to be more optimal and accurate than 30 degreesC. The Makler chamber was preferred to the Cell-vu, which induced a decrease of all semen motility parameters. The repeatability of the measures was good with intra-and inter-assay coefficients of variation below 10% and 20%, respectively, for most of measured parameters. An overestimation of semen concentration, increasing with dilution of semen, was observed when HTR-IVOS10 results were compared with the classical manual Makler cell evaluation. A significant decrease in semen motility parameters was recorded when high semen dilutions were used. Generated from the analysis of 42 mature fertile male beagle dogs, a description of semen motility parameters using the CASA system is presented to serve as reference when comparing Beagle ejaculates both in clinical and experimental studies.

Summarizing the motion of self-propelled cells: applications to sperm motility

Proper characterization of the motion of spermatozoa is an important prerequisite for interpreting differences in sperm motility that might arise from exposure to toxicants. Patterns of sperm movement can be extremely complex. On the basis of an exponential model that relates the discretely approximated curvilinear velocity to the tracking rate, we develop a statistic that indexes the predictability of the path for individual sperm. We summarize the path of each sperm using this and two other statistics: (1) the path displacement velocity and (2) linearity of movement. We apply the method to a set of rat sperm tracks representative of both normal and abnormal motion characteristics.

Use of a sperm analyzer for evaluating broiler breeder males. 1. Effects of altering sperm quality and quantity on the sperm motility index

A new instrument for assessing mammalian semen attributes, the Sperm Quality Analyzer, was evaluated as a potential tool for determining rooster sperm quality. The Sperm Quality Analyzer measures the "activity" of sperm in a semen sample as the sperm motility index (SMI). The SMI is defined as the number and amplitude of deflections in a light path per second as a result of sperm movement within a capillary tube. In the present study, effects of sperm concentration, viability, and motility on the SMI were evaluated. Peterson broiler breeder males (n = 40) were used as semen donors. In the initial experiment, semen was diluted from 2- to 25-fold and SMI readings were obtained. The SMI was very low in neat semen samples but increased when semen was diluted up to threefold. However, at dilutions greater than fivefold, the SMI decreased. Apparently, sperm concentration in undiluted semen is so great that sperm are unable to move freely within the capillary tube. Maximum SMI values were obtained at sperm concentrations of approximately 1 billion sperm per milliliter. When thawed, dead sperm were mixed with incubated, live sperm, the SMI decreased with decreasing sperm viability even though sperm concentration was constant. Obviously, fewer sperm move across the light beam as sperm mortality increases. When motile, aerobically incubated sperm were mixed at different rates with immotile, anaerobically incubated sperm samples, the SMI increased with increasing concentrations of motile sperm, whereas total sperm concentration was static. In addition, the SMI was strongly correlated with motility scores obtained by microscopic analysis. The Sperm Quality Analyzer provides an estimate of the overall quality of sperm from broiler breeder males by reflecting sperm concentration, viability, and motility in a single value, the SMI.

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.

Segmentation of sperms using the strategic Hough transform

A new method based on the Hough transform has been used for the quantitative estimation of the morphological characteristics of the sperm. Images of the sperms were acquired into the digital format using the optical microscope, CCD camera, and frame grabber. For each sperm in the image, the region of interest for the segmentation of the sperm head was selected using the density difference between the sperm head and background. The boundary of the sperm head was approximated with an ellipse and represented by five parameters. These five parameters representing an ellipse have been investigated by applying the Hough transform strategically. During the searching procedure using the Hough transform, we restricted the searching volume minimally and moved the next searching volume to the direction showing the steepest gradient of the estimation error. Also, we increased the parameter resolution from the three pixel distance to the one pixel distance. For the tested images, head boundaries of the sperms were estimated with an error of 1/2 pixel distance, and morphological parameters were calculated by the equations without further image processing. This new method separates sperm head based on the geometrical characteristic of the sperm and calculates morphological parameters simply from the derived boundary.

Assessment of sperm motion characteristics in infertile renal transplant recipients using computerized analysis

A total of 34 kidney transplant recipients (18 infertile and 16 fertile) and 31 nontransplant persons (15 infertile and 16 fertile) were included in this study. All subjects were assessed clinically and by measurement of basal concentrations of total testosterone, FSH, cyclosporine whole blood trough levels, serum creatinine, haemoglobin and semen analysis using computer-aided sperm analysis (CASA) as well as scrotal ultrasonography to evaluate testicular dimensions. Our results demonstrate a significant decrease (p < 0.05) in sperm concentration, the percentage of motile spermatozoa, straight line velocity (VSL), linearity (LIN) and velocity of average path (VAP) among infertile transplant patients in comparison with the fertile transplant group. Serum testosterone, FSH levels and testicular dimensions did not differ significantly (p > 0.05) between fertile and infertile transplant recipients. Both sperm concentration and VSL were inversely correlated to the cyclosporine whole blood trough levels (p < 0.05). The time spent on haemodialysis was inversely correlated (p < 0.05) with the percentage of motile spermatozoa and the amplitude of lateral head displacement (ALH). In conclusion, CASA is valuable in evaluation of sperm motility in infertile renal transplant patients. Stabilization of the cyclosporine whole blood trough level within the target therapeutic level and correction of anaemia (if any) could improve the fertility potential in kidney transplant recipients.

Measurement of the sperm motility index via the sperm quality analyzer and its relationship to other qualitative sperm parameters

Sperm parameters such as the concentration and percentage of motile spermatozoa are commonly used to assess semen quality. The sperm quality analyzer (SQA) is a device that detects variations in the optical density of motile spermatozoa, providing a sperm motility index (SMI) that is based on various sperm parameters including the concentration, morphology and acrosomal status of motile spermatozoa. The relationship between SMI values of frozen-thawed bovine spermatozoa undergoing swelling in a hypoosmotic medium (100 mOsm/L) and other sperm parameters were evaluated. Frozen semen specimens from 3 bulls were thawed and washed with Ham's F-10 supplemented with 3% BSA and split into 3 (0.2 mL) aliquots. The aliquots were diluted with 1.0 mL of Ham's F-10 (Aliquot 1), isotonic sodium citrate (Aliquot 2), and hypotonic sodium citrate (Aliquot 3). The osmotic pressure of the media used for dilution of Aliquots 1 and 2 was 300 mOsm/L, while that for Aliquot 3 was 100 mOsm/L. Following dilution, the aliquots were incubated for 30 min and manually assessed at 5-min intervals for the percentage and grade of motility (Grades 0 to 4) as well as for the percentage of swollen spermatozoa. Sperm samples were simultaneously evaluated by SQA to obtain the SMI values at the same 5-min intervals during the 30-min incubation. Significant correlations were observed between SMI values and other sperm parameters in Aliquot 3 (P < 0.05). The results indicated that the SMI values obtained from frozen-thawed bovine spermatozoa exposed to a 100 mOsm/L diluent, which causes optimal swelling of spermatozoa, are highly correlated to other sperm parameters. The SQA unit, as applied in this study, can be used for rapid and reliable screening of sperm samples.

Ultrastructural and biochemical analysis of sperm flagella from an infertile man with a rod-dominant retinal degeneration

This study examined the ultrastructural morphology and posttranslationally modified alpha-tubulin isoforms in the sperm flagella of a patient presenting with infertility and retinal degeneration. Clinical evaluation showed impaired motility and gross morphological abnormalities of the sperm and a rod-dominant retinal degeneration with midperipheral pigment clumping and scattered bone spicules. Other neurological indications included delayed neuroelectric transmission in the auditory brainstem and a temporal lobe seizure disorder. Ultrastructural analysis showed that 46% of sperm axonemes had missing and/or misplaced doublets compared with 10% to 12% in control subjects. ELISA analysis showed hypoacetylation of alpha-tubulin (30% of control) but normal levels of alpha-tubulin tyrosination. Tubulin acetyl-transferase specific activity was also 30% of control activity. These characteristics may be indicative of microtubule instability leading to the pathological consequences described.

Intracytoplasmic sperm injection facilitates fertilization even in the most severe forms of male infertility: pregnancy outcome correlates with maternal age and number of eggs available

OBJECTIVE

To evaluate, in a prospective study, the fertilization and pregnancy rates after intracytoplasmic sperm injection (ICSI) in infertile couples with severe male infertility.

DESIGN

Intracytoplasmic sperm injection was performed in 229 consecutive IVF cycles on 190 couples with rigorously defined severe male infertility or proven failure of fertilization in prior IVF cycles. Neither male nor female partners were chosen from a waiting list or on any other selective basis, including age, prior or anticipated ovarian response, or oocyte number or quality. There were no upper age limits, in no instance was donor sperm used for ICSI, and cycle cancellation rate was minimal.

SETTING

Private genetics and fertility center in Fairfax, Virginia.

MAIN OUTCOME MEASURES

Fertilization, transfer, and pregnancy rates were measured in ICSI-treated couples, and comparisons were made regarding both female age and strictly defined semen categories.

RESULTS

Two hundred six cycles (90%) resulted in ETs, with initiation of 52 pregnancies (25% per transfer, 23% per cycle). Thirty-eight of 52 (18% per transfer) were clinical pregnancies with established gestational sacs or were ongoing or delivered. Pregnancies were achieved even in older women but were more readily established in younger women producing larger numbers of metaphase II oocytes. The severity of semen abnormalities had some small effect on fertilization rate, but only actual necrospermia was associated with markedly decreased frequency of embryo formation. Pregnancy per transfer was similar across groups. In some cases, pregnancy was initiated with fewer than 100 viable sperm in the ejaculate.

CONCLUSIONS

Intracytoplasmic sperm injection is a very powerful new treatment for severe male infertility. Paradoxically, egg number and probably egg quality are now the main determinants of success in treating male infertility.

Development of an effective and simple insemination method for the in vitro fertilization of patients with male-factor infertility

An insemination method involving mechanical removal of the cumulus and multiple oocytes per dish (MRC-MOPD) was applied to achieve in vitro fertilization (IVF) of patients with male-factor infertility, and the prognosis of IVF and embryo transfer was evaluated. Although the fertilization rate of patients with male-factor infertility was only 41.4% (12/29) using standard insemination methods, a 73.0% (27/37) fertilization rate was achieved with the MRC-MOPD method. Moreover, 10 patients with male-factor infertility who were treated with the MRC-COPD method achieved clinical pregnancy. A comparison of the results in the 10 patients who were treated with both methods in common reveals that the MRC-MOPD method also increased the fertilization rate per oocyte. The rate of occurrence of polyploid fertilization did not increase, although large numbers of sperm were inseminated via the MRC-MOPD method. These results indicate that the MRC-MOPD method is an effective and simple insemination technique to achieve successful IVF of patients with male-factor infertility.

Correlation of zona-binding with oocyte maturation and sperm motility in rhesus monkeys by hemizona assay

The hemizona assay (HZA) in Rhesus monkeys was employed to study the correlation of zona-binding ability with sperm motility or with naturally developing oocytes at various maturational stages. Oocytes from unstimulated ovaries were retrieved within 2 hr from monkeys sacrificed for vaccine production (in reproductive season, but with their menstrual cycles not determined). Oocytes were divided into four groups based on their morphological maturation: 1) Oocytes surrounded by more than one cumulus layer (MC); 2) Oocytes retaining intact germinal vesicle nuclei (GV); 3) Oocytes with germinal vesicle breakdown showing distinct perivitelline space (PVS); and 4) Oocytes extruding the first polar body (PB1). The mean numbers of sperm bound to hemizona for PB1, PVS, GV, and MC groups were 132.9 +/- 12.0, 71.5 +/- 10.1, 36.1 +/- 4.0, and 20.1 +/- 2.9 (Mean +/- SE), respectively. The four groups showed significant differences from each other in sperm/egg binding ability (P < 0.01). The number of bound sperm significantly increased with oocyte maturation. The present study also showed that zona-binding ability was also affected by sperm motility. For sperm with 67.7% motility and sperm with 31.2% motility, the average numbers of bound sperm were 43.5 +/- 2.2 and 25.3 +/- 2.9 (Mean +/- SE), respectively. There was significantly higher binding ability for sperm with higher motility (P < 0.01). The results suggest that: 1) The rhesus monkey model can serve as a very sensitive model for studying sperm/egg interaction by HZA; 2) Sperm motility positively correlated with sperm/egg binding; and 3) Sperm/egg binding ability increases with oocyte maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-aided semen analysis variables as predictors of male fertility potential

A computer-aided semen analysis (CASA) was used to allow digitizing the motion of the spermatozoon. This procedure allows an objective means of judging semen quality, especially the translational movements of spermatozoa. Forty-three couples were included in the study. The average age of the male was 35.5 +/- 4.7 years and that of the female was 32.7 +/- 4.7 years. The average duration of infertility was 3.8 +/- 2.3 years. Using multiple linear regression analysis of 26 prognostic variables, a cluster of 8 variables significantly predicted pregnancy maximally. The 8 variables and the resultant multiple correlation coefficients were used to generate a multiple regression equation which allowed the correct separation of the population into fertile and infertile couples. The mean pregnancy predictor values of the fertile and infertile populations were significantly different using the analysis of variance.

Predictive power of sperm motion analysis in in vitro fertilization

The correlation between sperm motion characteristics and in vitro fertilization was studied in 160 cycles, divided in two groups: those with male subfertility (N=42) and those with tubal disease (N=118). The group with male subfertility showed inferior performance, as indicated by a lower fertilization rate per oocyte (40% versus 66%) and per pick-up cycle (67% versus 93%). These two groups exhibited no significant difference in the mean sperm velocity, linearity, amplitude of lateral head displacement, and beat cross frequency in the pre swim-up and post swim-up specimens. The two groups differed in pre and post swim-up sperm motility, pre and post swim-up concentration, pre swim-up cumulative velocity at 110 to 140 Amicrom/sec and post swim-up cumulative velocity at 130 microm/sec. Logistic regression analysis was used to determine those variables that would predict fertilization; pre swim-up count and post swim-up motility proved to be the significant determinants. The results indicate that assessment of motion by automated semen analyzers does not supplement conventional semen analysis in the ability to predict fertilization.

Influence of pentoxifylline on human sperm motility in asthenozoospermic individuals using computer-assisted analysis

This study was conducted to evaluate the in vitro effects of pentoxifylline on sperm motility from asthenozoospermic men. The sperm were prepared by a swim-up technique from the unprocessed semen. After centrifugation, sperm were resuspended in the presence or absence (controls) of 3.6 mM pentoxifylline in Earle's solution for up to 180 min. Sperm motility was measured using computer-assisted (Hamilton-Thorn Research) semen analysis. Pentoxifylline significantly increased the numbers of motile (+28-80%) and progressively motile (+54-117%) sperm over the 180 min studied. These changes were accompanied by increases in the progressive velocity (VSL, +11-44%) and curvilinear velocity (VCL, +12-22%) up to 120 min after exposure to the drug. Concomitant changes were observed in the amplitude of lateral head displacement (ALH, +5-17%) up to 60 min and the beat cross frequency (+16-34%) between 60 and 180 min. The results suggest that pentoxifylline consistently enhances both the numbers of motile and progressively motile sperm and the quality of their movement.

Association between human in vitro fertilization rate and pregnancy outcome: a possible involvement of spermatozoal quality in subsequent embryonic viability

A conventional view of mammalian fertilization is that the active component of the process: the spermatozoon, by virtue of its progressive motility and acrosomal enzymes, penetrates an otherwise passive oocyte. This concept has placed bias on spermatozoal normality as largely determining the outcome of fertilization; once this has been achieved then the contribution of the spermatozoon is often forgotten, and attention switches to the maternally derived "blue-print" for early embryonic development. Paternal genomic contribution is known to start at the eight-cell stage in the human, but this is usually after the time when early cleavage stage (2 to 8-cell stage) embryos are replaced in human assisted reproductive technologies (ART) procedures such as in vitro fertilization and embryo transfer (IVF-ET). Hence, fundamental abnormal contributions to embryogenesis derived from the fertilizing spermatozoon have often been ignored. Human IVF-ET has permitted far greater powers of analysis of the fertilization event, and fertilization success appears to be determined in such a system by three main factors: spermatozoal quality, oocyte quality, and quality of in vitro culture conditions (the gamete environment). If the second two factors are more carefully controlled than the first, as is the usual emphasis in routine human IVF practice, then any large variation in fertilization rates that are also significantly related to embryonic viability and ultimately pregnancy outcome, may be thought to be more directly associated with original quality of the fertilizing spermatozoon. An analysis of results of 758 IVF cases provides preliminary evidence to show that there is a close association between human in vitro fertilization rate and subsequent embryo viability following replacement. In accepting this hypothesis as a possibility, we should drastically change our attitude from one of the spermatozoon as a robust, simple initiator of embryonic development, and embrace the idea of the vulnerability of such germ cells both during and after their production, and how detrimental influences on this might profoundly affect embryogenesis after successful fertilization.

Kinetic activity of spermatozoa from fertile subjects and asthenozoospermic infertile patients

The motility characteristics of spermatozoa from asthenozoospermic semen were investigated and compared to the same parameters in fertile semen. The motility characteristics assessed by the CellSoft semen analyser (CRYO Resources Ltd, NY) were the following: curvilinear velocity (VCL), straight line velocity (VSL), amplitude of lateral head displacement (ALH), linearity (%LIN), and beat cross frequency (BCF). Analysis of the data indicated a decreased kinetic activity in the spermatozoa from the asthenozoospermic group which is expressed as a highly significant decrease (P < 0.002) in the VCL and VSL compared to velocities from normospermic samples. Moreover, percentage linearity and ALH were also statistically lower (P < 0.05) in this group. However, no difference was evidenced for the BCF.

The variability of measuring sperm concentration and motility as determined by computer assisted image analysis and visual estimation

Systems of computer-assisted image processing (CAIP) offer good reproducibility and low intra-assay variability between replicate analyses of the same sample. The correlation between these values and those obtained by directly microscopic observation can be well demonstrated. The comparability between systems of different manufacturers is sufficient and satisfactory. Thus, they are well-suited for the routine work in the andrologic laboratory. Since sperm parameters are used for the prediction of male fertility, it is important to know whether computer-assisted analysis improves the predictive power as compared to visual estimation. In our study we compared the variation of semen parameters between two semen samples of the same individual taken in an interval of at least 3 months, by using the CAIP and visual methods. Significantly close correlations between the two values were obtained by both methods. Values of cell concentration showed the highest correlation in both methods (r = 0.75). The lowest correlation, but also statistically significant, was observed in the values of locally motile cells (r = 0.54 for CAIP and r = 0.30 for visual determination). Although apparently higher in CAIP within method correlation coefficients did not show statistically meaningful differences between both methods. We conclude from our study that if values of sperm concentration and motility as measured by CAIP are compared to those obtained by visual measurement, the first method is not superior to the latter in terms of retest reliability.

Automated analysis of rabbit sperm motility and the effect of chemicals on sperm motion parameters

Appropriate software settings and optimum procedures were determined for the measurement of the motion parameters of rabbit spermatozoa by the CellSoft (Cryo Resources Ltd., Montgomery, NY) computer-assisted digital image analysis system. The system was used to follow motion parameter changes occurring in spermatozoa incubated for 6 hr with or without exposure to chemicals. Mean amplitude of lateral head displacement (AALH) increased over the 6 hr period, while curvilinear velocity (Vc) first increased and then decreased. Values for linearity (Lin), or beat cross frequency (BCF), were unchanged. The majority of spermatozoa progressed linearly, with rapid rotation of the sperm head, but subpopulations of spermatozoa with different swimming patterns appeared after 1-3 hr of incubation. Percentage motile sperm and Vc were most sensitive to the action of the compounds (pyrogallol, hydroquinone, ammonium oxalate, triethyl phosphite, and pinocolyl alcohol), while BCF was least affected. The decline in percentage of motile sperm was dependent on duration of exposure and chemical concentration. Mean Vc of the sperm population decreased rapidly upon chemical exposure and remained at a low value until motility ceased. The initial decrease in Vc was dependent on the concentration of the added compound. Motion-based indices--motility concentration (MCI50), motility time (MTI50), and velocity (VI)--were defined and used as toxicological endpoints. The rank order of these indices, the end point of the neutral red in vitro assay for cytotoxicity, and LD50 values for the five compounds were the same, suggesting that chemical inhibition of sperm motility may be useful as a method for the in vitro assessment of chemical cytotoxicity.

Antisera to calreticulin inhibits sperm motility in mice

Mouse sperm were rapidly immobilized when exposed to rabbit antisera against rat calreticulin. The inhibition of sperm motility was concentration dependent at dilutions 1:50-350. The velocity of sperm did not change significantly as long as they were motile. Neither motility nor velocity of sperm was affected by adding sheep antisera to bovine calmodulin. The antisera to calreticulin also inhibited in vitro fertilization of mouse eggs. Using the avidin-biotin-peroxidase complex method, the antigen was found to be localized in the acrosome of sperm. The results indicate that calreticulin is present in the acrosome of mouse sperm and may play an important role in sperm motility.

Laboratory methods for assessing human semen in epidemiologic studies: a consensus report

It is clear that additional methodologic work needs to be performed. Some data gaps described above are being actively investigated. Other standards were not addressed at this meeting; statistical handling of the data, differences among CASA machines, and factors to consider as potential confounders in analysis are just a few. These may be the subject of future workshops, which will also review progress made in the existing knowledge base. For now, this effort represents a first attempt to share information and to use it to encourage investigators in different laboratories to employ similar methods. In this way more direct comparisons among studies can be made, and our collective data base can be strengthened.

Clinical use and misuse of automated semen analysis

During the past six years, there has been an explosion of technology which allows automated machine-vision for sperm analysis. CASA clearly provides an opportunity for objective, systematic assessment of sperm motion. But there are many caveats in using this type of equipment. CASA requires a disciplined and standardized approach to semen collection, specimen preparation, machine settings, calibration and avoidance of sampling bias. Potential sources of error can be minimized. Unfortunately, the rapid commercialization of this technology preceded detailed statistical analysis of such data to allow equally rapid comparisons of data between different CASA machines and among different laboratories. Thus, it is now imperative that we standardize use of this technology and obtain more detailed biological insights into sperm motion parameters in semen and after capacitation before we empirically employ CASA for studies of fertility prediction. In the basic science arena, CASA technology will likely evolve to provide new algorithms for accurate sperm motion analysis and give us an opportunity to address the biophysics of sperm movement. In the clinical arena, CASA instruments provide the opportunity to share and compare sperm motion data among laboratories by virtue of its objectivity, assuming standardized conditions of utilization. Identification of men with specific sperm motion disorders is certain, but the biological relevance of motility dysfunction to actual fertilization remains uncertain and surely the subject for further study.

Fertilization failure and dysfunctions as possible causes for human idiopathic infertility

Consideration of the most common currently practiced laboratory assays for human spermatozoal fertility are discussed, with reference to the relevance of such assays to success or failure in human in vitro fertilization (IVF). Such IVF therapy should be the definitive challenge for human spermatozoal fertilization ability. However, when fertilization fails, is polyspermic, or is suboptimal, then questions concerning the step or steps in the process of fertilization which are dysfunctional remain unanswered. Quite possibly new assays need to be devised to address these problems, while in the meantime our present laboratory assay systems need to be improved to discern those defects in fertilization which operate in many cases of human idiopathic infertility.

Sperm motility index: a new parameter for human sperm evaluation

OBJECTIVE

The study was performed to evaluate the correlation between sperm motility index, a novel parameter of semen quality, and routine semen analysis parameters by microscopic evaluation.

DESIGN

Sperm motility index was measured by an electro-optical device, the Sperm Quality Analyzer (United Medical Systems Inc., Santa Ana, CA). Human semen samples covering the whole span of qualities were analyzed prospectively and simultaneously by both methods.

SETTING

Samples were collected from patients referred to university hospital infertility clinics.

PATIENTS, PARTICIPANTS

Nine hundred sixty-eight semen samples of 812 patients and healthy men were analyzed.

MAIN OUTCOME MEASURE(S)

Sperm motility index is a measurement of optical density fluctuations caused by motile cells; therefore, a positive correlation was anticipated between its values and semen motility parameters.

RESULTS

Sperm motility index values demonstrated statistically significant correlation with motile cell concentration, total cell concentration, and percent motile cells. They were also shown to reliably represent semen quality assessment obtained by two experienced andrologists.

CONCLUSIONS

The sperm motility index provides a reliable and objective reflection of semen motility parameters and quality.

The predictive value of zona-free hamster egg sperm penetration assay for failure of human in vitro fertilization and subsequent successful zona drilling

The value of various sperm parameters and the zona-free hamster egg sperm penetration assay (SPA) in predicting human in vitro fertilization (IVF) failure and subsequent successful fertilization with zona drilling was assessed. In 19 couples, throughout 31 IVF cycles, a total of 153 oocytes failed to be fertilized. In subsequent 12 cycles with zona drilling, 33 of 131 (25%) were fertilized. The incidence of teratospermia and asthenospermia was significantly higher in the study group than in the control, 74% versus 32% and 42% versus 5%, respectively. Although the mean values for the performance of sperm in SPA and fertilization of human eggs after zona drilling were remarkably similar (28 +/- 6 versus 28 +/- 4), there was no correlation between individual parameters (r = 0.15). Thus, whereas male factor infertility is more likely to be associated with teratoasthenospermia, neither the SPA nor other sperm parameters have any predictive value for failure in IVF. In addition, no criterion of sperm function has yet been identified that would eliminate oligoteratoasthenozoospermic males from consideration of IVF with zona drilling.

Evaluation of the Hamilton-Thorn 2030 motility analyser for routine semen analysis in an infertility clinic

In routine semen analysis of 242 patients the values of sperm concentration, sperm motility and progressive sperm motility were measured with the Hamilton-Thorn semen analyser (HT) and compared to the data obtained by conventional semen analysis according to the guidelines of the WHO. Overall, the HT gave higher values for sperm concentration (mean difference 21.7 +/- 46.2 x 10(6) ml-1, mean +/- SD). Motility values showed a correlation of 0.67 (slope 0.94, P less than 0.001) but were estimated lower by the HT than by conventional analysis (mean difference 7.3 +/- 21.7%); this was caused by the overestimation of sperm concentration. In the range from 0 to 50% motility the HT yielded lower values and higher values from 50 to 100% motility. Progressive motility values of the HT agreed better with conventional analysis (WHO categories a + b): the mean difference of all values was 0.5 +/- 19.5% (r = 0.74, slope = 1.0). The mean lateral head displacement measured by the HT increased with increasing sperm path velocity, but other significant correlations between sperm movement parameters could not be demonstrated. In many instances round cells and debris could not be distinguished from normal sperm. In conclusion, the HT system cannot replace conventional semen analysis in routine diagnosis.

Follicular fluid-induced acrosome reaction distinguishes a subgroup of men with unexplained infertility not identified by semen analysis

We compared the ability of sperm to undergo follicular fluid-induced acrosome reaction in vitro in fertile men and patients with unexplained infertility. After capacitation under optimum conditions, 28% of sperm from fertile men undergo acrosome reaction after follicular fluid exposure, whereas only 7% of the cells react spontaneously. In 15 men with unexplained infertility, 6 patients showed lack of acrosome reaction, whereas 9 men had sperm acrosome reactions similar to that of fertile men. However, in this cohort under study, semen characteristics of AR(+) and AR(-) patients were similar. In addition to inducing sperm acrosome reaction, follicular fluid also promoted significant changes in motion characteristics of capacitated sperm. Sperm curvilinear velocity (Vc) increased significantly after exposure to follicular fluid though linearity remained unchanged. The largest difference in cumulative Vc occurred at 90 microns/s. Assessing the ability of capacitated sperm to acrosome react may have clinical significance in predicting whether such sperm are capable of fertilizing an ovum.

Low acrosin activity in a subgroup of men with idiopathic infertility dose not correlate with sperm density, percent motility, curvilinear velocity, or linearity

The authors compared sperm acrosin activity with sperm density and cell motion characteristics in 21 normal fertile men and 25 patients with unexplained infertility. Under standardized and optimized conditions of abstinence and semen sample processing, we measured sperm acrosin activity in washed sperm from direct aliquots of semen and in aliquots of semen filtered through glasswool to remove dead cells and debris. Using washed sperm from semen, sperm acrosin levels in infertile men (median, 44 microIU/10(6) sperm) were significantly lower than values measured in fertile men (median, 67 microIU/10(6) sperm, P less than 0.01). After glasswool filtration, sperm acrosin activity was higher for both fertile and infertile men. Using washed sperm, 7 of 25 patients had acrosin activity consistently below values measured for fertile men; after glasswool filtration, values for 8 of 14 patients were below the normal range. For either fertile or infertile men, sperm acrosin activity showed no correlation with sperm density, percent motility, or either motion characteristic of curvilinear velocity (Vc40 microns/sec) or linearity (L3); and further, the low sperm acrosin activity of some infertile patients did not correlate with the motion co-characteristics measured at Vc40/L3, and the majority of patients with slower and/or less directional sperm had normal acrosin activity. From our data, we therefore conclude that sperm acrosin activity is independent of sperm motion characteristics.

Sperm motion characteristics in men with isolated hypogonadotropic hypogonadism treated with gonadotropin

The authors compared curvilinear velocity (Vc) and linearity (L) of sperm from fertile oligospermic men with isolated hypogonadotropic hypogonadism (IHH) to Vc and L of sperm from fertile normal men in order to determine if sperm motion analysis is better than sperm density as an indicator of fertility potential. Nine fertile men with IHH treated with exogenous gonadotropins and 20 fertile normal men were studied. Sperm density was significantly lower in the men with IHH compared with normal men (15.5 +/- 4.8 x 10(6)/ml versus 92.4 +/- 9.7 x 10(6)/ml; mean +/- standard error of the mean [SEM]; P less than 0.01) as was percent motility (51.4 +/- 4.7 versus 73.4 +/- 3.1; P less than 0.01). While a small but significant difference in Vc was noted between the groups at the 40 micron/second cumulative distribution point (P less than 0.01), no difference in L was found between the two groups. When the men with IHH were subgrouped according to sperm density (greater than 20 x 10(6)/ml versus less than or equal to 20 x 10(6)/ml, no differences in Vc were found between the subsets, but for L sperm were somewhat less directional for the subgroup with a density less than or equal to 20 x 10(6)/ml (P = 0.05). Coanalysis using both Vc and L parameters indicated that sperm from IHH patients were distributed similarly to sperm from normal men. However, sperm motion characteristics in men with unexplained infertility were different from values measured in normal men and IHH patients.(ABSTRACT TRUNCATED AT 250 WORDS)