Evaluation of computerized analysis of sperm movement characteristics and differential sperm tail swelling patterns in predicting human sperm in vitro fertilizing capacity

The hypo-osmotic swelling test: Is it a sperm vitality or a viability assay?

The first two editions of the World Health Organization laboratory manual described the determination of live spermatozoa by a dye exclusion method as a sperm "viability" test, whereas subsequent editions classified it as a "vitality" test, without providing an explanation for the reclassification. Additionally, the hypo-osmotic swelling (HOS) test, which assesses the functional integrity of the human sperm membrane, was placed in the same category as the dye exclusion test. Although the two terms might seem synonymous, the term "vitality" merely means "alive," whereas "viability" assesses qualities or physiological functions of a living entity. After comparing the morphological, physiological, and clinical findings obtained from dye exclusion testing vs. the HOS test, we conclude that the HOS test should be classified as a viability test, not merely as a vitality test.

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.

ABSENCE OF SPERM WITH RAPID MOTILITY IS NOT DETRIMENTAL TO IVF OUTCOME MEASURES WHEN ICSI IS USED

The objective of the current study was to investigate the association between rapid motility of sperm and IVF outcome when ICSI is used for insemination of oocytes. The first IVF cycle of women up to age 42 were evaluated. Patients were classified into groups by the presence/absence of sperm with rapid motility ("A" sperm) in the specimen before and after sperm preparation. Group 1 had 0% A sperm prewash and 0% A postwash (n = 45); Group 2 had 0% A sperm prewash but some A sperm postwash (n = 47); Group 3 had A sperm both pre and postwash (n = 141). Statistical analysis demonstrated no difference in the fertilization, PRs, or implantation rates in the three groups. These data suggest that absence of sperm with rapid motility postseparation of sperm from seminal plasma is not detrimental to IVF outcome when ICSI is used for insemination.

Review: in vitro spermicidal tests

This review analyzes in vitro spermicidal tests that have been used to evaluate the spermicidal activity of contraceptive products. Special requirements and processes in numerous technologies were also reviewed. Nonoxynol-9 (N-9) was used as an example of a vaginally delivered spermicidal agent, and its spermicidal potency was compared by various spermicidal tests, such as Sander-Cramer, computer-assisted semen analysis, hypoosmotic swelling test, cervical mucus penetration test, and flow cytometry, and advantages and disadvantages of each test were specified. This provides an insight into the different aspects of sperm functionality on which each spermicidal agent exerts its activity. A rationale of the best combination of in vitro spermicidal tests, with particular emphasis on a simple and efficient strategy that targets the complete fertility control, was explained.

A study of spermatozoal motility in type 1 diabetes mellitus

The aim of the study was to examine an aspect of male fertility in patients with Type 1 diabetes mellitus (n = 17) compared to healthy control subjects (n = 16) using parameters of sperm motility, measured using a computerized image analysis system (the Hamilton Thorn Research HTM-2030 Motility Analyzer), as indicators of potential fertility. Within the diabetic group no correlations were found between sperm motility and age, age of onset of diabetes, duration of diabetes or glycated haemoglobin. When the diabetic and control groups were compared, track speed, path velocity, progressive velocity, and lateral head displacement were not significantly different, whereas linearity and linear index, measures of straightness of swimming, were significantly greater in the diabetic subjects (59.2% vs 69.8%, p = 0.0005 and 76.4% vs 83.6%, p = 0.0016, respectively). We conclude that diabetic men, in the absence of complications, do not appear to be at a disadvantage in terms of sperm motility compared to healthy individuals.

Application of multivariate cluster, discriminate function, and stepwise regression analyses to variable selection and predictive modeling of sperm cryosurvival

OBJECTIVE

To develop a mathematical model that predicts sperm cryodamage based on the kinematic characteristics of seminal sperm as detected by computer-aided sperm analysis (CASA).

DESIGN

Computer-aided sperm analysis was performed on donor semen before and after freezing. An iterative multivariate statistical analysis technique was developed to identify sperm subpopulations and to select the best variables for modeling. Stepwise, multivariate regression was performed on the selected subpopulations to predict the post-thaw percentage of motile sperm from prefreeze kinematic values.

SETTING

Andrology laboratories, IVF laboratories, and sperm cryobanks.

PARTICIPANTS

Semen donors in an academic research environment.

MAIN OUTCOME MEASURES

Identification of predictive kinematic variables; number of sperm subpopulations per sample; number of kinematic variables per subpopulation; prediction error for subpopulation membership; and an equation for prediction of post-thaw percentage of motile sperm from prefreeze CASA variables.

RESULTS

The number of subpopulations for each specimen was predicted by 3 to 5 kinematic variables. Straight-line velocity (VSL) and linearity were the most commonly predictive primary variables, whereas curvilinear velocity and amplitude of lateral head displacement were the most commonly predictive secondary variables. The best linear model predicted the post-thaw percentage of motile sperm from the difference in VSL between the subpopulation with the highest value and the subpopulation with the lowest value in each prefreeze specimen.

CONCLUSIONS

A small number of consistent kinematic variables accurately described physiologic subpopulations of sperm in prefreeze and post-thaw specimens from different men. An equation based on the characteristics of these subpopulations predicts the post-thaw percentage of motile sperm (i.e., sperm recovery) from simple prefreeze kinematic variables. This equation could improve specimen screening by eliminating the requirements for freezing and thawing in order to identify a specimen's vulnerability to cryodamage.

The spermatozoal volume as indicative of the plasma membrane integrity (modification of the hypoosmotic swelling test). I. Methods

The aim of the present study was to establish a more differentiating indicator of plasma membrane integrity of spermatozoa than the classic version of the hypoosmotic swelling test according to Jeyendraan. Spermatozoa were prepared by density gradient centrifugation (90% Percoll) to select 'fertilization competent' spermatozoa only. After a second washing procedure sufficiently pure sperm cell suspensions were obtained. The volume distributions of these sperm cells were measured with a Coulter Counter at 25 degrees C after adaptation in 300 mosmolar NaCl solution resp. 150 mosmolar NaCl solution for 5 min. These volume distributions showed significantly different patterns for the isotonic and hypotonic stress situation in the simple salt solution. Moreover, the comparison of the response to hypoosmotic stress showed more than four reproducible characteristic patterns, promising well differentiated results for different sperm populations. The new method for the detection of hypoosmotic swelling effect might be a real and valuable functional parameter.

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.

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.

Novel parameters of human sperm hypoosmotic swelling test and their correlation to standard spermatogram, total motile sperm fraction, and sperm penetration assay

OBJECTIVE

To improve the accuracy of human sperm hypoosmotic swelling test by introducing new morphological evaluation parameters for this test.

DESIGN

Individual semen samples were processed, and the standard spermatogram, total motile sperm fraction, sperm penetration assay (SPA), and hypoosmotic swelling test were performed.

SETTING

Male infertility clinic and andrologic laboratory in a university medical center.

PATIENTS

One hundred eighteen subfertile men undergoing an infertility work-up.

MAIN OUTCOME MEASURES

The results of hypoosmotic swelling test were subdivided into four groups (hypoosmotic swelling test 1, 2, 3, 4) according to the different shapes of hypoosmotically affected spermatozoa tails.

RESULTS

The hypoosmotic swelling test 3 had the best correlation with the different sperm parameters: motility, total motile sperm fraction, concentration, and SPA. The hypoosmotic swelling test 1 showed a satisfactory interrelation for concentration and for total motile sperm fraction but no correlation for motility and SPA. The hypoosmotic swelling test 2 and the hypoosmotic swelling test 4 demonstrated no correlation at all with motility, concentration, morphology and SPA.

CONCLUSIONS

The precision of hypoosmotic swelling test may be improved by using the hypoosmotic swelling test 3 type of spermatozoa tail shape as the parameter for a normally functioning spermatozoa.

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.

The hypoosmotic swelling test: an update

The hypoosmotic swelling (HOS) test is a relatively new assay used to evaluate the functional integrity of the sperm's plasma membrane. In fact, more studies have been published on the applicability of the HOS test than any other new sperm indicator. The assay is based on the fact that fluid transport occurs across an intact cell membrane under hypoosmotic conditions until equilibrium is reached. Due to the influx of fluid, the cell will expand and bulge, especially in the tail, and this change can be readily observed with a phase contrast microscope. Earlier studies have yielded some confusion regarding the interpretation of the data. This review is an attempt to clarify and update the usefulness of the HOS test as a tool to evaluate the sperm function.

Evaluation of the hypo-osmotic swelling test in relation with advanced methods of semen analysis

The hypo-osmotic swelling test was claimed to assess an independent functional characteristic of human spermatozoa bearing relevance to their fertilizing capacity. To test this claim, we have studied the relationship between the result of the hypo-osmotic swelling test with that of conventional semen analysis and sperm motility patterns, the semen content of adenosine triphosphate, the staining pattern to acidified aniline blue, and the zona-free hamster oocyte test. The result of the HOS test is significantly correlated with all sperm characteristics except for the aniline blue stainability and the hamster oocyte test. The capacity of spermatozoa to react in a hypo-osmotic environment expresses the same functional information as the viability test using eosine staining. It is concluded that the hypo-osmotic swelling test does not add relevant information to that obtained by routine sperm analysis with regards to the fertilizing potential of semen.

Evaluation of testicular function

The evaluation of testicular function is based primarily on a detailed medical history, a careful physical examination, basal measurements of FSH, LH and testosterone and a routine semen analysis. In a patient with androgen deficiency, the diagnosis can often be made with these basic tests. The clinician will then decide on other investigations to localize the organic lesion and to plan further treatment for the patient. Sperm function tests are often performed in patients presenting with infertility. These newer tests may help to delineate the abnormality of the spermatozoa at each stage during the achievement of fertilizing capacity such as adequate forward motility, penetration of cervical mucus, acrosome reaction, development of hyperactivated motility, binding to the zona pellucida, and fusion with the oocyte. Currently, many of these sperm function tests depend on cumbersome bioassays with many limiting factors contributing to their availability, accuracy and precision. The development of biochemical tests as markers of sperm function may allow more precise definition of sperm functional abnormalities. With the continued improvement of computer-aided sperm analysis, objective motion parameter measurements are possible and morphological assessment are being developed. These newer objective methods of semen analysis have to be shown to be valuable in the clinical assessment of patients with testicular dysfunction.

Comparative study on the use of human follicular fluid or egg yolk medium to enhance the performance of human sperm in the zona-free hamster oocyte penetration assay

A prospective study was conducted on 61 unselected semen samples from infertile patients to compare the efficacy of human follicular fluid (hFF) or TEST-egg yolk medium treatment in enhancing sperm performance in the zona-free hamster oocyte penetration (HOP) test. Both hFF and TEST-egg yolk enhanced penetration scores significantly in the HOP test in comparison with the control swim-up sperm preparation. The TEST-egg yolk medium treatment, however, exhibited the highest penetration scores, and there were higher percentages of preparations passing the 10 or 20% penetration rate cut-off point with sperm exposed to the TEST-egg yolk medium than those exposed to hFF. These results indicate that modification of the original HOP-test protocol by incorporation of TEST-egg yolk medium gives a greatly increased penetration rate when compared to the addition of hFF in such a system.

Reappraisal of the hypo-osmotic swelling test to improve assessment of seminal fertility status

The hypo-osmotic swelling (HOS) test has been proposed as a useful assay for evaluation of the functional competence of the human sperm membranes. To assess this further, the HOS-test was evaluated in 187 semen samples collected from fertile men and from male patients consulting for infertility. These samples were classified as normal, oligo-, astheno- or oligoasthenozoospermic on the basis of their standard semen variables. The percentage of total sperm tail swelling and of sperm exhibiting different tail swelling patterns was recorded. In the fertile men and in the group of patients with normal semen variables, significantly more (P less than 0.001) HOS-reactive sperm were observed after hypo-osmotic treatment in comparison with those groups exhibiting abnormal semen parameters. Swelling of the sperm in a hypo-osmotic medium was highly correlated with both progressive motility (r = 0.62, P less than 0.001) and sperm viability (r = 0.65, P less than 0.001). A weak positive correlation was also observed between sperm swelling and sperm morphological features (r = 0.31, P less than 0.005) and between sperm swelling and sperm concentration (r = 0.31, P less than 0.005). No significant correlation was observed between sperm swelling and in-vitro sperm fertilizing capacity as assessed by the zona-free hamster oocyte penetration assay. However the majority of the semen samples (87.3%) showing a normal penetration rate (greater than or equal to 10%) also exhibited a 60% (or higher) reaction in the HOS-test.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of measurements of human sperm motility characteristics by the automated CellSoft system and time-exposure photomicrography

Human sperm motility characteristics in 28 semen samples with sperm concentrations less than 40 x 10(6) ml-1, as determined by the World Health Organization manual analysis (WHO, 1987), were measured by the automated CellSoft semen analyser (Cryo Resources Ltd, New York, NY, USA) using different system parameter settings (Mortimer & Mortimer, 1988a). The results were compared with those obtained by time-exposure photomicrographic (TEP) analysis. It was found that the settings of the minimum video frame rate and the threshold velocity used to distinguish motile from immotile sperm by the automated CellSoft system had a significant influence on measurements of percentage motility but not on linear velocity. At the five different parameter settings used in the present study, the automated CellSoft system gave significantly lower mean values for percentage motility in comparison with the WHO manual and TEP analyses. Measurements for linear velocity between the automated CellSoft system and TEP analyses were found not to be significantly different in these defined semen samples.

Computer-assisted assessment of human sperm morphology: usefulness in predicting fertilizing capacity of human spermatozoa

OBJECTIVE

The usefulness of sperm morphology to predict the outcome of human sperm fertilizing capacity was examined.

DESIGN, SETTING, PATIENTS

Semen samples from 50 male patients attending the infertility clinic of a tertiary referral institution were studied.

MAIN OUTCOME MEASURES

Sperm morphology was classified both by visual assessment and computer-assisted image analysis. In addition, morphometric analysis of the spermatozoa was measured by the morphologizer. Multivariate discriminant analysis was used to evaluate the usefulness of these morphology parameters for predicting the outcome of the zona-free hamster oocyte sperm penetration assay.

RESULTS

The manually derived percent of spermatozoa with normal and small head were selected to be of discriminating value in predicting the outcome of the zona-free hamster oocyte penetration test. The accuracy of correctly classifying the outcome of zona-free hamster oocyte penetration test by these two parameters in combination was 84%, whereas assessment of sperm morphology with morphometric analysis by the morphologizer selected a total of eight variables, which together predicted sperm fertilizing capacity with 74% accuracy. Addition of the morphologizer-derived parameters to those derived manually did not significantly improve the predictive value.

CONCLUSION

We conclude that the results of the zona-free hamster egg penetration test could be predicted using manual assessment of sperm morphology and computer-assisted morphometric analysis did not add further information.

Comparison of characteristics of human spermatozoa selected by the multiple-tube swim-up and simple discontinuous Percoll gradient centrifugation

The multiple-tube swim-up (MT-SU) and simple, discontinuous Percoll gradient centrifugation are two recent methods for the processing of human spermatozoa for assisted reproductive technologies. The present study was undertaken to compare the effects of these two methods on various parameters of spermatozoal qualities of normospermic semen samples. Both methods were found to select spermatozoa of better percentage motility, percentage normal morphology, viability, functional integrity of plasma membrane, movement characteristics including the curvilinear velocity, linearity of movement and head beat frequency, and in vitro fertilizing capacity with comparable degree of efficacy. It is concluded that both methods are effective for the separation of spermatozoa from normospermic semen samples for use in infertility treatment.

The diagnostic value of seminal adenosine triphosphate (ATP) in an in vitro fertilization (IVF) program

The level of adenosine triphosphate (ATP) was quantitated in semen samples used for in vitro fertilization of human oocytes. Seminal ATP level correlated with the concentration and percentage motility of spermatozoa but not with the in vitro fertilization rate of human oocytes. Seminal ATP measurement appears to have little diagnostic value in predicting the fertilizing capacity of spermatozoa as evaluated by the multivariate stepwise discriminant analysis.

Correlation of the hypo-osmotic swelling test, semen score and the zona-free hamster egg penetration assay in humans

The correlation between the hypo-osmotic swelling test, the modified Eliasson score for human semen analysis and the hamster egg penetration assay was examined. The results showed a weak but significant correlation between the group of subjects with swelling rates below 50% and the above 80% group. These groups showed hamster egg penetration assay rates of 9 +/- 14% and 39 +/- 29%, respectively (P less than 0.035). A significant correlation was also found between modified Eliasson scores (17 +/- 10 and 5 +/- 7, respectively) and swelling rates below 50% and above 70% (P less than 0.001). These results suggest that spermatozoa showing a low swelling rate have a poor fertilizing capacity. Therefore, the swelling tests and analysis of the patients semen can be used to discriminate sperm quality.

Variation of movement characteristics with washing and capacitation of spermatozoa. II. Multivariate statistical analysis and prediction of sperm penetrating ability

Fifty semen samples were studied by computer-assisted semen analysis before testing in the sperm penetration assay (SPA). Twenty-one concentration and movement measurements were obtained from each sample on sperm in semen, after washing and swim-up, and again after an 18-hour capacitation period. Discriminant analysis was then used to define a function from these measurements that would classify the SPA results as above or below a 10% penetration rate. A significant function was identified using the following variables: sperm concentration and motility in semen, and mean curvilinear velocity, linearity, and amplitude of lateral head displacement of washed sperm. Movement measurements of capacitated spermatozoa were not useful predictors in this analysis. The overall accuracy of this function for predicting SPA results was 72%. These findings demonstrate that computer-derived measurements of sperm movement provide biologically useful information regarding sperm function, and, in addition, emphasize the importance of multivariate techniques in the analysis and description of human sperm motion.