The role of the laboratory in the handling of epididymal sperm for assisted reproductive technologies

Recovery, isolation, identification, and preparation of spermatozoa from human testis

In some cases, human spermatozoa to be used for in vitro fertilization are processed from testicular or epididymal biopsies collected in the clinic or operating room. An appropriately equipped Andrology or Embryology Laboratory is required. Sterility must be maintained at all stages from collection and transport to identification and processing to insemination or cryopreservation. The technologist must be able to properly process and identify spermatozoa from aspirates, seminiferous tubules or pieces of testicular tissue. Recovery of undamaged spermatozoa from tubules or tissue requires mincing, squeezing, or vortexing the tissue, usually without the need of enzymatic digestion. A motility stimulant such as Pentoxifylline is commonly used to calculate the number of functionally competent spermatozoa. After recovery, spermatozoa may be used immediately for IVF-ICSI, incubated overnight prior to IVF-ICSI, or cryopreserved for future use. Methods for identifying, purifying, and determining the number and motility of spermatozoa during these processes are presented.

Retrieval and cryopreservation of sperm from spermatocele fluid

OBJECTIVES

To evaluate the amount, motility, and viability of sperm in fluid aspirated from naturally occurring spermatoceles and to investigate the effect of cryopreservation of sperm retrieved from spermatoceles. Assisted reproductive technologies have led to successful pregnancies and deliveries using sperm harvested from the epididymis and/or testis of infertile men.

METHODS

Aspiration of spermatocele fluid and analysis of the fluid obtained was performed on 20 patients before elective spermatocelectomy. Randomly selected samples (n = 5) were washed using a 70% Percoll gradient, and repeated semen analysis was performed. The washed specimens were cryopreserved in liquid nitrogen, and repeated semen analysis was performed on the thawed specimens.

RESULTS

All spermatoceles (n = 20) had viable sperm present (count range 54 x 10(4) to 326 x 10(6)) and 16 (80%) of 20 contained motile sperm. The average percentage of motile sperm was 5%. The average sperm motility and average percent viability of sperm recovered after Percoll gradient improved compared with sperm in the initial spermatocele aspirates (motility 5%, range 0% to 25% and viability 36%, range 2% to 91% before Percoll vs. motility 13%, range 2% to 38% and viability 39%, range 10% to 92% after Percoll). Sperm retrieved after cryopreservation demonstrated reduced motility and viability; however, motile and viable sperm were recovered from all washed and cryopreserved samples.

CONCLUSIONS

Our results suggest that spermatocele fluid may contain sufficient numbers of sperm for use with assisted reproductive technologies. Motile and viable sperm can be recovered after cryopreservation and storage of sperm obtained from a spermatocele. Spermatocele fluid may be an additional source of sperm for assisted reproductive technologies.

Cryopreservation of epididymal sperm

The advent of ICSI and the perfecting of freezing protocols for sperm samples that in the pre-ICSI era would not have been frozen, allows now routine cryopreservation of epididymal sperm regardless of their quality and quantity. There are two methods to retrieve epididymal sperm: microsurgical epididymal sperm aspiration (MESA) and percutaneous epididymal sperm aspiration (PESA). The majority of the literature has focused on the technique of MESA to obtain sperm on the claim that the amount of sperm retrieved with PESA might not be sufficient to allow cryopreservation. However, there are no data on cryopreservation and ICSI with epididymal sperm collected with PESA technique. In this study, a total of 68 consecutive cycles of PESA, of which 46 were performed with fresh epididymal sperm and 22 with frozen/thawed specimens were retrospectively analyzed. In the fresh epididymal group (n = 46), 446 eggs were injected and 207 cleaving embryos were obtained (fertilization rate of 46%). In the cryopreserved epididymal sperm group (n = 22), 216 eggs were injected and 115 cleaving embryos were obtained (fertilization rate of 53%, P = NS). There were 18 pregnancies (39%) with 17 (37%) delivered/ongoing in the fresh group, while there were 11 (50%) with 9 (41%) delivered/ongoing in the frozen group (P = NS). Epididymal sperm for cryopreservation was available in 44 of the 46 PESA cycles. Additionally, in the fresh group, 19 couples had excess embryos for cryopreservation while in the frozen group, ten couples had excess embryos for cryopreservation. A total of 17 frozen embryo transfer with epididymal sperm from PESA were analyzed. Of these, 12 FET were from embryos from the fresh epididymal group and three pregnancies with livebirths (25%) were recorded. Five FET were performed with extra embryos from frozen epididymal sperm and two (40%) pregnancies with livebirths were obtained. In summary, these data show that epididymal sperm obtained by PESA can be successfully cryopreserved in order to avoid future retrievals procedures and fertilization and pregnancy rates are similar between fresh and cryopreserved epididymal sperm. It is also reported for the first time that the transfer of frozen embryos obtained with either fresh or frozen thawed epididymal sperm leads to the same pregnancy'and delivery rate.

Approaches for obtaining sperm in patients with male factor infertility

OBJECTIVE

To describe methods of sperm retrieval for intracytoplasmic sperm injection (ICSI) in patients with male factor infertility and to review the clinical results using sperm from the different sources.

DESIGN

The literature on sperm-obtaining methods and ICSI was reviewed. Studies related to this topic were identified through MEDLINE.

RESULTS(S)

This review describes the evolution of sperm retrieval methods. Sperm can be obtained by microepididymal sperm aspiration (MESA), percutaneous sperm aspiration (PESA), and testicular sperm extraction (TESE), from patients with congenital absence of the vas deferens or acquired vas obstruction. When ICSI is performed with ejaculated, epididymal, or testicular sperm, good fertilization and pregnancy rates are achieved without significant differences among the various sperm sources. The original percutaneous sperm aspiration method has been modified slightly and yields successful results.

CONCLUSION(S)

Viable pregnancies can be achieved with ICSI by using not only ejaculated sperm, but also epididymal and testicular sperm. Microepididymal sperm aspiration, percutaneous sperm aspiration, modified percutaneous sperm aspiration, and testicular sperm extraction can be considered standard procedures to treat male factor infertility.

Microinsemination techniques for the treatment of patients suffering agenesia of the vas deferens

Thirty cycles of microsurgical epididymal sperm aspiration were performed on 27 patients presenting agenesia of the vas deferens. Two techniques of microinsemination were used, depending on the quality of the sperm preparation: subzonal sperm microinjection and microdroplet insemination. The results obtained by both microinsemination procedures are presented and discussed.

Efficacy of microsurgical epididymal sperm aspiration (MESA) and intracytoplasmic sperm injection (ICSI) in obstructive azoospermia

PURPOSE

Our purpose was to test whether micromanipulation using subzonal insemination and intracytoplasmic sperm injection could improve the poor fertilization and pregnancy rates obtained when attempting in vitro fertilization in patients with congenital absence of the vas deferens and unreconstructable obstructive azoospermia with microsurgically retrieved epididymal spermatozoa.

RESULTS

Conventional in vitro fertilization (group A; 14 cycles), subzonal insemination (group B; 13 cycles), and intracytoplasmic sperm injection (group C; 28 cycles) were carried out in 55 treatment cycles. Fertilization rates for groups A, B, and C were 16.1, 31.4, and 48.6%, respectively (P < 0.05). Clinical pregnancy rates for groups A, B, and C were 7.1, 7.7, and 32.1% (P < 0.05), respectively. In five cycles, intracytoplasmic sperm injection using epididymal sperm from alloplastic spermatoceles was performed and two clinical pregnancies (40%) were obtained.

CONCLUSIONS

The combined microsurgical epididymal sperm aspiration and intracytoplasmic sperm injection procedure is highly effective in improving the fertilization and pregnancy rate in congenital absence of the vas deferens and unreconstructable obstructive azoospermia. Furthermore, alloplastic spermatoceles may be useful for repeat sperm aspirations.

Successful use of pentoxifylline in male-factor infertility and previous failure of in vitro fertilization: a prospective randomized study

OBJECTIVE

Our objective was to determine whether the use of pentoxifylline (PF) would improve the in vitro fertilization (IVF) rate and outcome in couples with male factor infertility and previous failure of fertilization in vitro.

DESIGN

This prospective randomized controlled study was conducted in an assisted conception unit.

MATERIALS AND METHODS

Forty-nine couples with previous failed fertilization in vitro attributable to male factor or male-factor infertility without previous IVF were recruited for the study. Controlled ovarian hyperstimulation was performed using a combination of gonadotropin releasing hormone agonist and human menopausal gonadotropin. Oocytes of the same grade and maturity were inseminated with spermatozoa treated with PF or control spermatozoa. A maximum of three embryos was replaced after 48 hr and all other embryos were cryopreserved. Pregnancy outcome was followed up and evidence of fetal or neonatal anomalies reported.

RESULTS

A significantly higher fertilization rate occurred in the group where oocytes were inseminated with spermatozoa treated with PF compared with controls (56.3 versus 30.7%; P < 0.05). Fertilization occurred in 45 of the 49 cycles (92%). In seven cycles, only the oocytes that were inseminated with spermatozoa treated with PF fertilized, in contrast to only one cycle where the oocytes inseminated with control sperm fertilized (P < 0.05). Fifty-seven PF and 31 control embryos were replaced and 11 clinical pregnancies occurred. Three of the pregnancies occurred in the seven cycles in which only PF embryos were replaced, one in the single cycle where control embryos were replaced and seven from the 37 cycles in which both PF and control embryos were replaced. There was no evidence of congenital malformations in any of the offsprings resulting from this study.

CONCLUSION

This study suggests that PF improves the fertilization rate and outcome in couples with male factor infertility and poor fertilization rates. This study does not suggest any increase in teratogenicity or evidence of congenital malformations in pregnancies following IVF cycles where PF was used.

Successful fertilization, pregnancy, and birth using epididymal sperm frozen 24 hours after conventional oocyte insemination

OBJECTIVE

To assess if epididymal sperm cryopreserved 24 hours after exposure to oocytes in conventional IVF can be successfully used for intracytoplasmic sperm injection (ICSI) in a subsequent cycle.

DESIGN

Case report.

SETTING

University of California, Irvine, Center for Reproductive Health.

PATIENTS

Two men with obstructive azoospermia requiring microsurgical epididymal sperm aspiration, IVF, and ICSI.

INTERVENTIONS

Freezing of epididymal sperm 24 hours after egg exposure in conventional IVF and subsequent use for assisted fertilization in a new cycle.

MAIN OUTCOME MEASURE

Frozen-thawed epididymal sperm survivability and maintenance of fertilization and pregnancy capacity.

RESULTS

At the time of sperm aspiration procedure (cycle I) a total of 30 oocytes were available for insemination. Of these, 15 were used for conventional IVF resulting in 2 embryos (13%) and 15 were used for ICSI, resulting in 3 embryos (20%). Sperm was cryopreserved 24 hours after conventional IVF and thawed 6 months later in a new cycle. Upon thawing, sperm were still found to be motile and at this time (cycle II) only assisted fertilization was used. Of 27 oocytes injected, 12 (44%) produced normal, cleaving embryos. One singleton pregnancy with the birth of a healthy infant girl was achieved after the tubal transfer of 5 embryos.

CONCLUSION

The birth of a normal, healthy infant girl with epididymal sperm frozen 24 hours after exposure to oocytes in conventional IVF emphasizes the value of freezing any aliquot of epididymal sperm, even if the motility is very low, to avoid additional surgery in the male. From a basic science standpoint, this observation may renew interest in the study of sperm cryopreservation after occurrence of acrosome reaction and hyperactivation.

Functional and structural characteristics of human epididymal spermatozoa retrieved by transcutaneous aspiration

The present paper describes the development of a simple, repeatable technique for transcutaneous aspiration of epididymal spermatozoa in patients with inoperable excretory azoospermia. Some functional and structural parameters of the retrieved spermatozoa were also evaluated. Epididymal spermatozoa from patients and ejaculated spermatozoa from fertile donors showed similar percentages of acrosome-reacted cells after incubation for 6 or 15 h in capacitating medium. Penetration of zona-free hamster oocytes, expressed as the percentage of penetrated ova, was significantly lower (p < 0.01) for spermatozoa from patients than for ejaculated spermatozoa from fertile donors. The percentage of epididymal spermatozoa with stable nuclei in sodium dodecyl sulphate was lower (p < 0.001) than for ejaculated spermatozoa from fertile donors. A positive linear correlation (r = 0.74, p < 0.005) was evident between the oocyte penetration rate and the percentage of spermatozoa with stable nuclei. In conclusion the percutaneous retrieval of epididymal spermatozoa in excretory azoospermia allows collection of motile spermatozoa, which can be evaluated for their structural and functional characteristics before repetition of the technique for retrieval of spermatozoa for assisted fertilization techniques.

Choosing among different technical variations of Percoll centrifugation for sperm selection

We compared the efficiency of different methodological variations of the centrifugation through discontinuous Percoll gradients (PC) to improve semen samples in the laboratory. Five different combinations of the number, volume and density of PC layers were assayed in 14 semen samples presenting various qualities. Each specimen was divided into five aliquots and processed simultaneously. The percentage of spermatozoa showing optimal movement (VAP > 30 microns s-1 and STR > 80%) after PC selection when the number of gradients was reduced to three or two (PC-3: 43.3%, PC-2: 41.3%) and when the volume of layers was diminished to 0.5 ml (mPC-3: 44.2%, and mPC-2: 48.1%), was higher than in classical columns with four gradients of 1 ml (PC-4: 26.3%). The absolute recovery of optimal sperm was better with PC-2, mPC-2 and mPC-3. In samples showing low concentration or motility of spermatozoa, mPC-2 was the most effective technique. PC-2 and mPC-2 showed a tendency to eliminate more red blood cells contaminating the samples. Straight line velocity and straightness were similarly improved by all the methods. We conclude that the technique of PC centrifugation with only two gradients is simpler and more effective for sperm selection and in cases of poor samples can be used with low-volume layers.

In vitro retrieval of epididymal sperm: a new approach to achievement of pregnancy for post-testicular azoospermia

OBJECTIVE

To determine the efficacy of in vitro retrieval of epididymal sperm for pregnancy induction for obstructive azoospermia patients.

DESIGN

Patients were divided into three groups as follows: [1] ductal obstruction with previous epivasostomy (group I); [2] ductal obstruction with previous epididymitis (group II); and [3] ductal obstruction without previous epivasostomy or epididymitis (group III).

SETTING

A university teaching hospital.

PATIENTS

Twenty infertile males with obstructive azoospermia.

INTERVENTIONS

Epididymides were detached surgically just after harvest of oocytes from corresponding wives and severed into three pieces (caput, corpus, and cauda). Each piece was dissected and squeezed in Ham's F-10 medium to retrieve the sperm. After completion of sperm preparation, IVF of their wives' oocytes and zygote intrafallopian transfer followed.

RESULTS

Overall pregnancy rate by in vitro retrieval of epididymal sperm was 35% (7 of 20). The rate for group I was 0%, or 0 of 6; for group II the rate was 0%, or 0 of 3; and for group III it was 63.6%, or 7 of 11.

CONCLUSIONS

In vitro retrieval of epididymal sperm can be a new method for inducing pregnancy in surgically incorrectable obstructive azoospermia.

In vitro fertilization in couples with previous fertilization failure using sperm incubated with pentoxifylline and 2-deoxyadenosine

OBJECTIVE

To evaluate whether incubation of spermatozoa with both pentoxifylline and 2-deoxyadenosine would improve fertilization rates in couples with previous IVF failure.

DESIGN

Autocontrolled design in which sibling oocytes were inseminated at random in vitro with spermatozoa treated or not treated by pentoxifylline and 2-deoxyadenosine.

MEAN OUTCOME MEASURES

Oocyte quality, sperm motility, fertilization in vitro, and embryo quality.

RESULTS

Sperm motility was found optimized by metabolic stimulation using pentoxifylline and 2-deoxyadenosine. The mean fertilization rate per patient was 33.1% in the treatment group compared with 37.0% in the control group. The mean cleavage rate per patient was 79.6% for treatment versus 68.7% for control embryos. No differences in embryo quality were noted.

CONCLUSION

The results of this study demonstrate that an indiscriminate use of pentoxifylline and 2-deoxyadenosine is not beneficial to fertilization in couples with previous IVF failure. Further prospective research may be needed to assess the benefit of pentoxifylline and 2-deoxyadenosine in patients selected by preliminary functional in vitro tests.

Four cases of bladder exstrophy in two families

Bladder exstrophy is a rare congenital anomaly, caused by abnormal development of the cloacal membrane. To our knowledge, 18 familial patients with this malformation have been described. Two sets of familial cases with bladder exstrophy are reported here: two cousins and a mother and son and the published reports of the 18 familial cases among 682 index patients with bladder exstrophy are reviewed. Ultrasonography is advocated as the investigation of choice for early prenatal diagnosis.

Correlation between epididymal length and fertilization rate in men with congenital absence of the vas deferens

OBJECTIVE

To investigate whether the variable length of the epididymides in men with congenital absence of the vas deferens might have a correlation with IVF and pregnancy rate results.

DESIGN

Microsurgical retrieval of epididymal sperm from men with congenital absence of the vas deferens and their use for IVF.

SETTING

Center for Reproductive Health, University of California, Irvine, California.

PATIENTS

One hundred eight men with confirmed diagnosis of congenital absence of the vas deferens enrolled in the microsurgical epididymal sperm aspiration and IVF program.

INTERVENTIONS

Measurement in centimeters of the epididymal length at the time of the sperm aspiration procedure.

MAIN OUTCOME MEASURE

Rates of fertilization and pregnancy according to the epididymal length.

RESULTS

Three groups were identified: group I (n = 29), epididymal length between 0.5 and 1.9 cm; group II (n = 66), length between 2.0 and 4.0 cm; and group III (n = 13), length in excess of 4.0 cm. Although the aspiration site was the proximal caput for each case, patients of group III had the highest fertilization and pregnancy rate (24% and 43%, respectively). Patients with the shortest epididymis (group I) had the worst IVF outcome (fertilization rate 7% and pregnancy rate 7%) whereas in group II the fertilization rate was 13% and the pregnancy rate was 18%.

CONCLUSION

This study demonstrates that epididymal sperm from men with congenital absence of the vas deferens having a longer epididymis have a better IVF rate. A long epididymis can allow [1] the arrival of more frequent waves of fresh sperm whereas in a short epididymis the system is completely congested and occupied by old and senescent sperm, [2] less obstructive damages, and [3] a back flow of biochemical factors produced in the more distal segments that could ultimately enhance the fertilization capacity of proximal epididymal sperm.

Fertility and the use of assisted reproductive techniques in the adult male exstrophy/epispadias patient

These three cases exemplify, in increasing order of complexity, how the common sense application of already successful techniques might be applied to augment the chance of pregnancy in this group of patients. We believe this to be the first report specifically outlining measures that may assist this group in their goal of pregnancy achievement. To our knowledge, vasal sperm aspiration has never been used for this indication.

Effects of pentoxifylline on sperm motility and hyperactivation in normozoospermic and normokinetic semen

OBJECTIVE

To determine the effects of in vitro incubation with pentoxifylline on sperm motion characteristics of spermatozoa from normozoospermic, normokinetic specimens.

DESIGN

Prospective, controlled experiment.

SETTING

Andrology laboratory, university-based fertility center.

PARTICIPANTS

Healthy, untreated male partners of couples attending the fertility center.

INTERVENTION

Each specimen was washed, pelleted by centrifugation, then resuspended in human tubal fluid medium (HTF). Two portions were incubated at 37 degrees C, one with pentoxifylline (final concentration = 1 mg/mL = 3.6 mM) and the other without pentoxifylline (control). After 1 hour, the pentoxifylline-treated portion was divided: one half was washed to remove pentoxifylline, then further incubated in HTF; the other half remained incubated in HTF with pentoxifylline.

MAIN OUTCOME MEASURES

Motility, hyperactivation, amplitude of lateral head displacement (ALH), curvilinear velocity (VCL), straight line velocity (VSL), linearity (LIN), beat-cross frequency.

RESULTS

Incubation with pentoxifylline did not increase motility, VSL, LIN, or beat-cross frequency but did significantly increase HA, VCL, and ALH at 1, 2, and 4 hours, compared with control. Incubation in control medium without pentoxifylline did not significantly increase any of the parameters measured. After 24 hours of incubation with or without pentoxifylline, all parameters measured were significantly decreased, with the exception of LIN.

CONCLUSIONS

Pentoxifylline does not increase percentage motility of washed spermatozoa in capacitation medium. Enhancement of sperm HA by pentoxifylline in capacitation medium occurs with normozoospermic, normokinetic semen specimens. This effect persists for up to 4 hours when pentoxifylline is removed from the medium after 1 hour of incubation.

Microsurgical aspiration of sperm from the epididymis: a mobile program

We report data from 25 microsurgical aspirations of the epididymis on 22 men. There were 14 men with congenital absence of the vas, 6 with failed vasoepididymostomy, 1 with adult cystic fibrosis and 1 with a childhood hernia repair. The specimens were used for assisted reproductive technologies, including in vitro fertilization and tubal embryo transfer. The protocol for aspiration, ovulation induction and sperm processing evolved during the course of these studies, and the patients were classified into 2 groups on the basis of methodology. Seventeen procedures were performed for the in-house in vitro fertilization team but 8 other procedures were done for nearby in vitro fertilization centers, and the final prepared sperm samples were transported as part of our mobile program. Group 1 patients underwent standard aspiration techniques, standard ovulation induction and sperm processing by wash and swim up. Among this group there were no fertilizations or pregnancies with 8 in-house and 2 transported specimens. Group 2 patients had leuprolide suppression before ovulation induction, direct intratubular aspiration and a complex sperm preparation, including pentoxifylline stimulation, mini-Percoll filtration and incubation with human follicular fluid. Among this group there were 2 fertilizations and 1 pregnancy with 9 in-house cases, and 3 fertilizations and 2 pregnancies with 6 transported specimens. These results suggest that a mobile program for microsurgical aspirations of sperm from the epididymis and in vitro fertilization or tubal embryo transfer is feasible within the framework of a strict protocol.

Analysis of factors contributing to success in a program of micromanipulation-assisted fertilization

OBJECTIVE

To determine factors important to clinical success in micromanipulation-assisted in vitro fertilization (IVF).

DESIGN

Procedures invoked in two separate series of micromanipulation-assisted IVF cycles, one unsuccessful (series I) and the other successful (series II), were compared in an effort to identify changes that led to clinical success.

SETTING

University-based IVF clinic.

PATIENTS

In both IVF series involving micromanipulation, patients consisted of infertile couples who fit any of five categories of male-factor related infertility. The female patients underwent controlled hyperstimulation for oocyte retrieval and the oocytes were inseminated normally or were subjected either to partial zona dissection or subzonal sperm insertion to assist fertilization. Results in all groups were compared between the two patient series.

RESULTS

In the successful series II, a noticeable improvement in fertilization rate and embryo quality was observed compared with series I. A significant increase in the percentage of patients reaching embryo transfer, the pregnancy rate per transfer, and the pregnancy rate per retrieval were noted in series II; a 25% ongoing pregnancy rate per retrieval was observed overall in this successful group, with "ongoing" defined as manifestation of at least a fetal sac on ultrasound with no detectable problems. Patients with a mixed transfer of embryos derived from manipulated and normally inseminated oocytes had a 75% rate of pregnancy per transfer in series II. Differences between the two series could not be attributed to patient selection or biases in selection of oocytes relegated to micromanipulation. However, oocyte handling, micromanipulation, and culture protocols differed significantly between the two series in that temperature and pH of oocytes was better controlled, and micromanipulation time was minimized in series II.

CONCLUSION

Success in micromanipulation depends on maintenance of the oocyte in a stable and supportive environment throughout the micromanipulation procedure. It is also important to minimize trauma to the eggs by performing micromanipulation rapidly and with minimal distortion of the egg. Patients with a poor fertilization rate in standard IVF may experience a substantial increase in the likelihood of pregnancy when micromanipulation-assisted fertilization is performed on some eggs.

Relationship of epididymal sperm antibodies to their in vitro fertilization capacity in men with congenital absence of the vas deferens

OBJECTIVES

To test, using the immunobead binding technique, for the presence of antisperm antibodies on epididymal sperm, in epididymal fluid, and in serum of men with congenital absence of the vas deferens. To evaluate the in vitro fertilization (IVF) capacity of human epididymal sperm in the presence of antisperm antibodies.

DESIGN

Prospective. At the time of oocyte insemination, sperm from the proximal caput epididymis or vasa efferentia were tested by direct immunobinding technique. The epididymal fluid and serum were tested by indirect immunobinding technique.

SETTING

Center for Reproductive Health, University of California-Irvine.

PATIENTS

Forty-five patients with congenital absence of the vas deferens participating in the microsurgical epididymal sperm aspiration and IVF program.

MAIN OUTCOME MEASURE

Incidence of antisperm antibodies to epididymal sperm and their relationship with IVF results.

RESULTS

Sixteen men (35%) tested positively to the direct immunobead test on epididymal sperm; 7 (16%) were positive in epididymal fluid and 13 (29%) were positive in serum. Five pregnancies (31%) occurred in the positive group of which two were from patients who had sperm binding of 100% for immunoglobulin (Ig)G (all over sperm surface) and 90% (midpiece, tail) and 50% (tail, tiptail), respectively, for IgA. Five pregnancies (18%) were obtained in the negative group. No statistical difference was observed in the overall fertilization rate between the two groups.

CONCLUSION

Human epididymal sperm and epididymal fluid retrieved from men with congenital absence of the vas deferens can react positively to immunobead test. However, the presence of antisperm antibodies do not seem to impair the IVF capacity of epididymal sperm.

Penetration of zona-free hamster oocytes using human sperm aspirated from the epididymis of men with congenital absence of the vas deferens: comparison with human in vitro fertilization

OBJECTIVES

To assess the ability of sperm aspirated from the epididymis of men with congenital absence of the vas deferens to penetrate zona-free hamster oocytes. To directly compare the performance of human epididymal sperm in the zona-free hamster oocyte sperm penetration assay (SPA) with the results of human in vitro fertilization (IVF).

DESIGN

Sperm penetration assay was carried out with epididymal sperm retrieved microsurgically, and with ejaculated sperm obtained from fertile donors (internal controls). For direct comparison, SPA was performed with the same epididymal sperm sample used for IVF.

PATIENTS, PARTICIPANTS

Men with congenital absence of the vas deferens undergoing sperm aspiration as part of their infertility treatment and control donors who provided ejaculated sperm.

RESULTS

Epididymal sperm penetrated SPA with a score of 0% to 30%. The SPA scores for internal controls using ejaculated sperm was 30% to 71%. Linear regression analysis of the association between penetration scores in SPA and fertilization rate in IVF indicated a positive correlation that was highly significative.

CONCLUSIONS

These findings using SPA confirm previous reports on the fertilizing potential of human epididymal sperm and its ability to produce normal pregnancies. The good correlation between SPA and human IVF using epididymal sperm suggest that SPA is an excellent bioassay to test laboratory experimental conditions for improving fertilizing capacity of human epididymal sperm.