Influence of pentoxifylline in severe male factor infertility

Pentoxifylline initiates motility in spontaneously immotile epididymal and testicular spermatozoa and allows normal fertilization, pregnancy, and birth after intracytoplasmic sperm injection

PURPOSE

Pentoxifylline (PF) has been used to enhance sperm motility in many in vitro fertilization programs. The twofold purpose of this study was to determine whether PF stimulates fresh or frozen epididymal and testicular totally immotile spermatozoa and whether it can be used to select viable spermatozoa for intracytoplasmic sperm injection (ICSI).

METHODS

To test the effect of PF on motility, 10 samples of totally immotile spermatozoa were incubated for 10 min with 3.6 mM PF. Motility was initiated in all cases (14.8% mean motility after PF treatment of five samples of fresh or frozen epididymal spermatozoa and 13.6% mean motility of five samples of fresh or frozen testicular spermatozoa). To assess PF for selection of viable spermatozoa before ICSI, we compared the outcome of ICSI in 20 cycles using fresh or frozen epididymal or testicular PF-treated immotile spermatozoa and 139 control ICSI using fresh or frozen epididymal or testicular spontaneously motile spermatozoa.

RESULTS

Fertilization rates were similar in the PF and control groups (45.2% vs. 51.0%). Embryo quality and division stages at the time of transfer were comparable. Six pregnancies occurred in PF-ICSI group (30.0% per cycle vs. 26.6% in control group) including two deliveries of healthy children and four ongoing pregnancies.

Relationship of total motile sperm count and percentage motile sperm to successful pregnancy rates following intrauterine insemination

PURPOSE

This study sought (i) to investigate the relationship between postwash total motile sperm count and postwash percentage motile sperm in predicting successful intrauterine insemination and (ii) to determine the minimal postwash total motile sperm count required to achieve pregnancy with intrauterine insemination.

METHODS

Five hundred four women, who underwent 1636 intrauterine insemination cycles with their partner's sperm for infertility treatment from 1993 through 1995, were included in this retrospective study. All patient charts were reviewed for age, infertility etiology, ovarian stimulation regimens, semen characteristics, and treatment outcome. To determine the relationship between total motile sperm count and intrauterine insemination outcome, patients were grouped as (1) less than 0.5 million, (2) 0.5 to 1 million, (3) 1 to 5 million, (4) greater than 5 million, and (5) greater than 20 million.

RESULTS

Similar live birth rates (per cycle) were seen among the postwash total motile sperm count groups: group 1, 3.5%; group 2, 2.4%; group 3, 7.0%; group 4, 6.9%; and group 5, 7.0% (P = 0.37). However, regardless of the postwash total motile sperm count, the postwash motility predicted intrauterine insemination success at a cutoff value of 40%.

CONCLUSIONS

The percentage of postwash sperm motility, and not the postwash total motile sperm count, can predict successful intrauterine insemination outcome. Such information can be useful in counseling patients regarding their chance of success with intrauterine insemination and in determining when alternate methods of assisted reproduction may be a better approach.

Correlation between the motility of frozen-thawed epididymal spermatozoa and the outcome of intracytoplasmic sperm injection

The purpose of this study was to investigate if the outcome of ICSI was influenced by epididymal sperm motility in frozen-thawed specimens. A total of 18 ICSI treatment cycles using spermatozoa retrieved by microsurgical epididymal sperm aspiration (MESA) were analysed retrospectively. Cryopreservation of epididymal spermatozoa was performed when enough epididymal aspirates were collected. Sixty-nine out of 126 oocytes injected with spermatozoa retrieved by MESA were fertilized, giving a fertilization rate of 54.8%. Out of 18 embryo transfer cycles, 6 (33.3%) achieved pregnancies. Fresh epididymal spermatozoa were used in 5 cycles while frozen-thawed epididymal spermatozoa were used in 13 cycles for ICSI. The fertilization rates were 68.6% (35/51) in the former group and 45.3% (34/75) in the latter group, respectively. There was a significant difference between the two groups (p < 0.05). In ICSI treatments using fresh epididymal spermatozoa, the cells used for injection were all motile. However, motile epididymal spermatozoa could be used in only five ICSI treatment cycles after freeze-thawing. In 6 cycles, only immotile sperm were used for injection of frozen-thawed spermatozoa. The fertilization rate in each group was 68.4% (13/19) and 31.6% (12/38), respectively. There was a significant difference between these groups (p < 0.01). These results indicate that the outcome of ICSI was influenced by sperm motility in frozen-thawed epididymal specimens. When no sperm motility could be recovered after freeze-thawing even with chemical treatments, consideration should be given to retrieving fresh epididymal spermatozoa again to achieve a better fertilization rate in such patients.

Effects of vasoactive intestinal peptide on human sperm motility

Sperm flagellar activity is modulated by cAMP. In target tissues, vasoactive intestinal peptide (VIP) stimulates adenyl cyclase activity, which elevates intracellular cAMP levels and activates protein kinase activity. This study investigated the effects of VIP on motility of sperm from 17 subjects. Motile activities, monitored before (0 min, baseline) and for 40 min after incubation with VIP (0.2 microgram/mL cell suspension), were analyzed by computer-assisted semen analysis. The data (mean +/- SEM) are expressed as percentages of baseline values and changes were compared by trend analysis for interval level measures by repeated measures analysis of variance orthogonal polynominal contrasts. The addition of VIP significantly increased motile sperm concentration (110 +/- 17% [10 min], 132 +/- 15% [20 min], 152 +/- 18% [30 min], 125 +/- 18% [40 min]; p < .02) and sperm with rapid straight-line motility (V > 25 microns/s) (167 +/- 20%, 174 +/- 19%, 173 +/- 23%, 141 +/- 16%; p < .02). Mean track speed (micron/s) was increased (125 +/- 12%, 134 = 9%, 129 +/- 12% and 126 +/- 12%; p < .02), while mean progressive velocity, amplitude of head displacement, and beat frequency were not affected by VIP. These results indicate that VIP stimulates sperm motile activity by cAMP-mediated phosphorylation of axonemal proteins.

Modulation of sperm tail protein tyrosine phosphorylation by pentoxifylline and its correlation with hyperactivated motility

OBJECTIVE

To assess the effect of pentoxifylline on human sperm functions that are crucial to fertilization.

DESIGN

Prospective, controlled study.

SETTING

Academic tertiary care institute.

PATIENT(S)

Healthy male sperm donors.

INTERVENTION(S)

The effects of pentoxifylline (3.6 mM) on hyperactivated motility, sperm binding to the zona pellucida, and sperm protein tyrosine phosphorylation were evaluated.

MAIN OUTCOME MEASURE(S)

Hyperactivated motility was assessed by computer-assisted motion analysis, and tight binding of sperm to homologous zonae pellucidae was examined using the hemizona assay. Sperm protein phosphorylation was evaluated using indirect immunofluorescence with an antibody to phosphotyrosine (PY20).

RESULT(S)

Pentoxifylline significantly stimulated hyperactivated motility at 1 hour and 4 hours; it also significantly increased sperm binding to the zona pellucida and enhanced sperm tail tyrosine phosphorylation at 4 hours under capacitating conditions. There was a statistically significant correlation between hyperactivated motility and sperm tail protein phosphorylation.

CONCLUSION(S)

Pentoxifylline stimulates sperm functions that are essential to achieving fertilization under in vitro conditions in sperm obtained from fertile men. The enhancement of hyperactivated motility is associated with the stimulation of sperm tail tyrosine phosphorylation, suggesting a causal relation and the involvement of a modulatory effect after cyclic adenosine monophosphate-dependent phosphorylation of intermediate proteins.

Pentoxifylline stimulates various sperm motion parameters and cervical mucus penetrability in patients with asthenozoospermia

Pentoxifylline (PTX) was incubated in vitro with human spermatozoa to examine its effects on sperm motility characteristics and bovine cervical mucus penetrability (BCMP). Sperm motion parameters were assessed by computer-assisted motion analysis (CASA) using HTM-IVOS and BCMP was evaluated using the Penetrak kit. In vitro incubation with PTX (1 mg ml-1; 3.6 mM, 30 min) did not significantly change percentage motility, average path velocity (VAP), straight-line velocity (VSL) or beat cross frequency (BCF) of spermatozoa from normozoospermic or asthenozoospermic samples. However, it significantly increased curvilinear velocity (VCL), amplitude of lateral head displacement (ALH) and hyperactivated motility (HA), and significantly decreased linearity (LIN) of spermatozoa from both samples. Pentoxifylline was found to increase BCMP scores for spermatozoa from asthenozoospermic samples, but did not affect scores for spermatozoa from normozoospermic samples. Bovine cervical mucus penetrability (BCMP) was found to be positively and significantly correlated with the percentage motility of both non-PTX-treated and PTX-treated spermatozoa for asthenozoospermic samples. These results demonstrated that PTX enhanced several motion sperm parameters as well as BCMP in asthenozoospermic samples and suggest a potential use of the methylxanthine in infertile patients with motility defects undergoing artificial insemination.

Sperm separation in patients with urogenital infections

A total of 196 patients attending the Center of Dermatology and Andrology, Giessen, Germany, were examined for fertility problems. Polymorphonuclear elastase, reactive oxygen species (ROS) and the number of round and peroxidase-positive cells were investigated in addition to routine semen analysis. The ejaculates were also analysed before and after sperm separation by means of swim-up or glass wool filtration. In 20 cases of leukocytospermia, sperm concentration, motility, viability, production of reactive oxygen species, and the number of peroxidase-positive cells were evaluated before and after glass wool filtration. The results show that ROS production by viable spermatozoa is highly correlated with the concentration of PMN elastase and the number of both peroxidase-positive and round cells. Multiple regression analysis with motility as dependent parameter showed the number of round cells (n = 91; r = -0.332; P = 0.0030) to be the most important parameter affecting motility, while ROS mainly affects the viability of spermatozoa (n = 69; r = 0.250; P = 0.0107). In the case of leukocytospermia, glass wool filtration significantly reduced the number of peroxidase-positive cells and ROS production (P = 0.0098 and P = 0.0005, respectively). Receiver operating characteristic (ROC) curve analysis for ROS production in the ejaculate using a concentration of 1.000 ng ml-1 PMN elastase as decisive parameter resulted in a cut-off value of 49,489.9 counts 10(-7) viable spermatozoa. The statistical parameters were: Sensitivity: 63.2%, specificity: 100%, positive predictive value: 100%, negative predictive value: 36.1%.

Increase of intracellular calcium is not a cause of pentoxifylline-induced hyperactivated motility or acrosome reaction in human sperm

OBJECTIVE

To investigate the effects of the phosphodiesterase inhibitor pentoxifylline on hyperactivated motility and acrosome reaction in human sperm and to determine whether its stimulatory effects occur via increased intracellular calcium levels.

DESIGN

Prospective study.

SETTING

Academic tertiary care facility.

PARTICIPANT(S)

Healthy male donors.

INTERVENTION(S)

The effects of pentoxifylline on hyperactivated motility, acrosome reaction, and intracellular calcium were studied and compared with the effects of progesterone. Thapsigargin, a known mobilizer of intracellular calcium, also was used as positive control.

MAIN OUTCOME MEASURE(S)

Hyperactivated motility was assessed by computer-assisted sperm motion analysis using the HTM-IVOS, acrosome reaction was evaluated with the fluorescent probe fluorescein isothiocyanate-labeled Pisum sativum agglutinin, and intracellular calcium was determined by fura-2 using spectrofluorometry.

RESULT(S)

Pentoxifylline significantly increased both hyperactivated motility and acrosome reaction. Enhancement of hyperactivated motility by pentoxifylline in the capacitation medium persisted for up to 5 hours after pentoxifylline was washed from the medium. It also enhanced the percentage of acrosome-reacted spermatozoa after 4 hours of incubation. These effects occurred in the presence of a marginally significant decrease in intracellular calcium.

CONCLUSION(S)

Pentoxifylline stimulates hyperactivated motility and acrosome reaction in spermatozoa from fertile men. Its stimulatory effects occur through mechanism(s) other than increase in intracellular calcium.

Direct measurement of the tail beat frequency of human sperm by flash light synchronization

Based on the synchronization between a periodic vibration and flashing light, we designed a device to determine the flagellar beating frequency of human sperm. The head of a spermatozoon was either held by the tip of a micropipette operated with a micromanipulator or adhered by itself on the surface of a glass slide when the sperm swam out of the micropipette into the fresh Ham's F-10 medium. The beat frequency of the flagellum was measured by synchronization of the frequency-adjustable flash light built on an inverted microscope. The light frequency synchronizer included a controller, a pulse generator, a signal counter, and a flash illuminator. During each measurement, the spermatozoon was transferred to the center of the observing field and the frequency generator created a series of signals which developed flashing signals onto the sample plane. When the vibration of the flagellum was observed as a constant two-step-like movement after frequency adjustment, the beating frequency was read from the signal counter and the count was twice that of the beat frequency of the sperm tail. As the flash signal was decreased to half of this frequency, an apparently immobilized sperm flagellum was observed and the exact beating frequency could then be determined. This device was then used to measure the effect of pentoxifylline on sperm motility. The results showed that the increase of tail beat frequency as measured by this device is well correlated with the increase of beat cross frequency as detected by a computer-assisted semen analyzer. These findings suggest that this flash light synchronization device is a reliable and useful system for the assessment of sperm motility.

In vitro fertilization for male infertility: when and how?

The first observation that in vitro fertilization (IVF) was useful for treating oligozoospermia and oligoasthenozoospermia was reported by Fishel and Edwards in 1982. This was followed by a series of cases indicating the value of IVF in such cases. Conventional IVF has been modified and refined to achieve increased rates of conception in cases of male factor infertility. Methods such as high insemination concentration IVF for the treatment of teratozoospermia and microscopic IVF for the treatment of oligozoospermia have had some impact on fertilization and pregnancy rates; however, reports of success are varied. The recent advent of micromanipulation and, in particular, intracytoplasmic sperm injection (ICSI) has overshadowed the use of these modified IVF procedures. Because of the high fertilization and pregnancy rates achieved with ICSI, other micromanipulation techniques (subzonal insemination and partial zona dissection) have been abandoned; there have also been suggestions that other more conventional techniques, i.e. IVF, should also be abandoned and that ICSI become the sole technique for the treatment of infertility. The rapid increase in the number of centres using ICSI has led to extreme pressure for individual units to achieve high fertilization and pregnancy rates and there is a temptation to assign all patients to ICSI treatment. It is important that, in this highly competitive environment, new techniques are not applied haphazardly and reduced to the mere injection of gametes and achievement of pregnancy regardless of the cause of infertility. In his 1986 IVF--Historical Perspective, Fishel quoted Auguste Comte: 'to understand science it is necessary to know its history'. IVF has much recent history in animal and also human work. Although ICSI is the most significant therapeutic advance in male infertility treatment, its application to human IVF is only 4 years old, with a paucity of animal studies on which to rely. For this reason IVF still plays a very important role in the treatment of male factor infertility and should only be ruled out when it has failed previously or the number of available sperm is limited.

Clinical assessment of male infertility in the era of intracytoplasmic sperm injection

This communication outlines the major causes of infertility in the male and, where indicated, the application of in vitro fertilization and intracytoplasmic sperm injection in their treatment. It also points out that there are many types of infertility in the male where other methods of treatment are also successful and where reproductive technology is unnecessary.

Effects of pentoxifylline on sperm motility in normogonadotropic asthenozoospermic men

Forty-seven normogonadotropic men with idiopatic asthenozoospermic were divided at random: group I (N = 22) received placebo and group II (N = 25) received 1200 mg of pentoxifylline/day during 6 months. Semen analysis was performed basal and at 3 and 6 months of the study period. No statistical changes in serum hormone concentration were found, nor in volume, sperm counts, viability, and morphology before and after treatment. Sperm motility increased following pentoxifylline treatment after 3 and 6 months from 25.5 (21.0-30.0) to 35.5 (31.5-39.0) (p < .00001) and to 42.0 (38.0-46.0) (p < .00001), respectively. Although in the placebo control cases some changes were observed in the sperm motility, they were less significant. Furthermore, progressive motility only in grade A increased with pentoxifylline from 2.5 (0.0-6.0) to 12.0 (6.0-19.5) (p < .001) at 3 months and to 22.5 (17.0-26.0) at 6 months (p < .00001). In conclusion, pentoxifylline had an additional effect rather than placebo and was useful treatment in these cases of male factor infertility.

Motility stimulant effects of prostasome inclusion in swim-up medium on cryopreserved human spermatozoa

The chance of obtaining a fertilization and establishing a pregnancy increases with the number of motile spermatozoa that can reach and interact with the oocyte after the time of insemination. In an attempt to increase the recovery of freeze-thawed and motile spermatozoa, the swim-up medium was supplemented with prostasomes and some other effectors. Swim-up media supplemented with prostasomes were superior in comparison to the other effectors investigated in the recovery of motile spermatozoa for insemination. These results suggest that prostasome inclusion in swim-up medium might be of benefit in improving results in assisted reproductive technologies using freeze-thawed spermatozoa.

Effects of Chinese herbal medicine on sperm motility and fluorescence spectra parameters

Hochu-ekki-to is a Chinese herbal medicine that has been used for unexplained male infertility with some favorable clinical results. However, the detailed mechanisms of the effect of this medicine on male infertility have not been disclosed. This study investigated the effects of Hochu-ekki-to on sperm motility of human semen. Sixteen semen samples were obtained from 14 normal volunteers. Semen samples were incubated with 1, 10, and 100 micrograms/mL of Hochu-ekki-to solution in 5% CO2, 37 degrees C for 1-6 h, and the motility was compared with that of the control groups (the untreated semen and the semen incubated with phosphate-buffered saline). The motility of sperm in 10 and 100 micrograms/mL of Hochu-ekki-to solution for 1-6 h was significantly higher than that of the control groups. One microgram/milliliter of Hochu-ekki-to solution also maintained higher sperm motility after 4-6 h incubation compared with the control groups. Previous reports showed that sperm motility correlated significantly with fluorescence intensity peaks from both spermatozoa and semen plasma. However, the fluorescence intensity at 622 nm excited at 488 nm from spermatozoa fractions in each group was not significantly different. It would appear that the enhanced sperm motility induced by Hochu-ekki-to is mediated by improvement of the circumstances of semen rather than that of spermatozoa-related factors.

Could in vitro fertilization with a modified sperm preparation technique be an option to micromanipulations?

PURPOSE

This study evaluated the efficiency of in vitro fertilization with a modified sperm preparation technique for male infertility, to avoid systematic recourse to ICSI.

METHODS

The sperm function stimulants pentoxifylline, 2-deoxyadenosine, and follicular fluid were used during the sperm preparation of IVF trials for two groups of patients: couples with long-standing infertility and previous IVF failures and couples with male-factor infertility scheduled for their first treatment.

RESULTS

Forty-nine attempts were performed in the first group. The overall fertilization rate (percentage of zygotes with two pronuclei 18 hr after sperm insemination) was 30% and the clinical pregnancy rate per transfer was 33%. For the second group, 30 attempts were performed. The fertilization rate was 29.6% and the clinical pregnancy rate was 62.5% per transfer. The total number of recovered motile sperm appears to be a significant parameter: a cutoff value of 0.25 million motile sperm recovered after capacitation treatment has a good prognostic value for choosing between IVF with sperm enhancers and ICSI.

CONCLUSIONS

The described modified IVF could constitute an alternative to the systematic use of ICSI.

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.

The effects of pentoxifylline on the generation of reactive oxygen species and lipid peroxidation in human spermatozoa

The aims of this study were to compare the in vitro effects of 3.6 mM and 7.2 mM pentoxifylline on the ability of spermatozoa to generate reactive oxygen species (ROS) and on lipid peroxidation (LPO). Semen samples were obtained from 10 asthenozoospermic men who had been previously identified as producing ROS after addition of Phorbol 12-myristate 13-acetate (PMA) during the screening of patients attending with male factor infertility. Spermatozoa were prepared by a swim-up technique from unprocessed semen and divided into 3 aliquots. To the control aliquot [A] an equal volume of BWW medium was added. To aliquots B and C an equal volume of BWW medium containing pentoxifylline was added to obtain final concentrations of 3.6 and 7.2 mM, respectively. ROS production was measured from peak luminescence (mV 10(-7) sperm) using a lucigenin chemiluminescent probe. LPO was also measured in the medium surrounding the spermatozoa after 30 min exposure to pentoxifylline using the thiobarbituric acid (TBA) assay for malondialdehyde (MDA). The reduction in ROS production was significantly greater in the samples exposed to 7.2 mM pentoxifylline as compared with the control and 3.6 mM pentoxifylline samples. There was no significant difference in peak luminescence between control and 3.6 mM pentoxifylline specimens. Both concentrations of pentoxifylline caused comparable reductions in MDA concentration in the medium (P < 0.05) surrounding the spermatozoa compared with control after 30 min exposure. Extracellular ROS generation may damage surrounding healthy spermatozoa. These findings suggest that higher concentrations of pentoxifylline are protective against ROS release in susceptible spermatozoa and may also reduce collateral LPO.

Sperm kinematics of cryopreserved normozoospermic specimens after artificial stimulation

OBJECTIVES

Cryopreservation of semen is associated with reduced motility after thawing, resulting in a decreased pregnancy rate. Artificial stimulation of motility has been used in fresh semen samples. This study measured the effect of motility stimulants on various motion characteristics and other sperm functions using cryopreserved semen.

METHODS

Frozen semen samples from healthy donors were thawed, and motility stimulants were added in vitro and incubated for 60 minutes. The percentages of motile spermatozoa in each specimen and other motion characteristics were measured. In addition, spermatozoon's viability, membrane integrity, and ability to penetrate bovine cervical mucus were studied after addition of stimulants.

RESULTS

Percentage motility and all other motion characteristics improved after stimulation with pentoxifylline, caffeine, or 2-deoxyadenosine. Linearity did not significantly differ in the control samples after adding any of the stimulants. Viability, membrane integrity, and penetration ability did not improve significantly and were comparable with control values.

CONCLUSIONS

Pentoxifylline, caffeine, and 2-deoxyadenosine can stimulate sperm motility and other motion characteristics. This may be beneficial in the cryopreservation of sperm from normal donors and oligozoospermic patients for use in assisted reproduction.

Effect of pentoxifylline added to freezing media on subsequent post-thaw hypoosmotic swelling test and other semen parameters

This study evaluated the effects of pentoxifylline (PTX) on post-thaw semen parameters as well as the hypoosmotic swelling (HOS) test. Fourteen samples were evaluated for volume, count, motility, % grade A sperm, and HOS test. Two aliquots were frozen, one in freezing medium and the other in a 3 mM solution of PTX and freezing medium. Both groups were frozen in liquid nitrogen vapors for 30 min. Thawing was performed at 37 degrees C for 15 min, followed by a wash with 2 parts 0.5% HSA/MHTF to 1 part sample. Pellets were resuspended in 0. MHTF and then evaluated as described above. In addition, motility was evaluated 2 h post-thaw. Following freeze-thaw, the mean motile densities were similar (17.5 x 10 motile/mL vs. 20.4 x 10(6) motile/mL for PTX and control, respectively). Two hours post-thaw, the PTX group had a mean sperm motility of 31.3% vs. 37.7% for the control group (p > .05). There were no significant differences in % grade A sperm in PTX (13.0%) vs. control (12.0%). Similarly, HOS scores did not improve following cryopreservation (43.0% and 50.6% for PTX and control, respectively). Thus, no improvement was found by freezing sperm with PTX.

An evaluation of the effect of pentoxifylline on sperm function and treatment outcome of male-factor infertility: a preliminary study

OBJECTIVE

Our objective was to study the effect of pentoxifylline (PF) on fertilization rates in couples with previous failure of fertilization and male-factor infertility and to determine the predictive value of conventional semen analysis parameters in selecting the couples who would benefit from the elective use of PF in IVF.

DESIGN

This prospective controlled study was conducted in an assisted conception

METHODS

Sixty-nine couples with previous failed IVF cycle, who had a low fertilization rate and/or male-factor infertility, were recruited to the study. Multiple follicular development was induced using the same protocol of human menopausal gonadotropin and gonadotropin releasing hormone analogue in both cycles. The oocytes were inseminated with spermatozoa treated with PF. The fertilization rates in the PF cycle were compared to the reference cycle based on semen analysis parameters and previous fertilization rates.

RESULTS

In couples with male infertility, the fertilization rate improved significantly, from 17 to 50% in PF cycles (P < 0.001). A significant improvement in fertilization rate was also demonstrated in couples with previous poor fertilization, < 30% (P < 0.01), particularly in those with a very low fertilization rate, < 20% (P < 0.001). Although there was an overall improvement in fertilization rates in couples with male-factor infertility, there was no cutoff value in sperm motility that would make a significant difference in the impact of PF on fertilization rates.

CONCLUSION

Couples with poor fertilization rates in vitro benefit with a significant improvement in fertilization by the elective use of PF. The improvement is most significant in couples with previous complete failure of fertilization and poor fertilization rates, < 30%.

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.

Sperm stimulants can improve fertilization rates in male-factor cases undergoing IVF to the same extent as micromanipulation by partial zona dissection (PZD) or subzonal sperm insemination (SUZI): a randomized controlled study

PURPOSE

Our purpose was to evaluate the efficacy of direct insemination (IVF), micromanipulation by partial zona dissection (PZD), and subzonal sperm insemination (SUZI) using sperm-treated with pentoxifylline (PF) +/- 2-deoxyadenosine (2DA).

RESULTS

The overall fertilization rate achieved was similar for all three fertilization techniques (33.1, 30.2, and 26.9% for IVF, SUZI, and PZD, respectively). Patients who had reduced fertilization in previous IVF attempts showed improved fertilization with sperm stimulants, either PF alone or PF in combination with 2DA in standard IVF. In certain cases, SUZI or PZD gave significantly improved fertilization rates in comparison to IVF.

CONCLUSION

Selective use of sperm stimulants in IVF can achieve fertilization for the majority of male-factor cases. However, PZD and SUZI techniques are useful, especially when sperm stimulants fail to achieve fertilization or achieve poor fertilization in direct insemination.

The effect of pentoxifylline on sperm motility, oocyte fertilization, embryo quality, and pregnancy outcome in an in vitro fertilization program

OBJECTIVE

To study the effect of pentoxifylline on sperm motility, oocyte fertilization, embryo cleavage, and quality as well as pregnancy outcome on asthenospermic patients participating in an IVF program.

DESIGN

Prospective randomized study.

SETTING

Private IVF unit.

PATIENTS

Ninety-seven couples, 24 of whom were repeating IVF. Two semen specimens were obtained from each patient and each specimen was divided equally into two parts, nontreated (control semen) and pentoxifylline-treated (treated semen).

MAIN OUTCOME MEASURE

Sperm progressive motility, oocyte fertilization.

RESULTS

Overall and progressive motility did not differ significantly between the two semen specimens. There was a significant increase in the progressive motality of the pentoxifylline-treated semen compared with control semen. No significant difference was noticed between control and treated semen in fertilization rate, cleavage rate, embryo quality, and pregnancy rate. The percentage of patients who fertilized only with control semen (9.3%) was not significantly different from that of patients who fertilized only with treated semen (10.3%). Couples who were repeating IVF did not show significant difference in fertilization between the present study and previous attempts.

CONCLUSION

Our results showed that although the sperm progressive motility is improved after pentoxifylline treatment, it is doubtful whether this effect is of any clinical significance.

Effect of pentoxifylline on human sperm motility and fertilizing capacity

The effect of pentoxifylline (PF) treatment on human sperm motility and fertilizing capacity was assessed in 43 couples undergoing IVF/ET, as well as in 84 couples treated with AIH/IUI. Sperm motility increased following PF treatment in asthenospermic samples (n = 12) from 39.2 +/- 1.5 to 45.5% +/- 2% (p = .05), in oligoasthenospermic (n = 40) from 38.1 +/- 1.6 to 43.6 +/- 1.7% (p = .001), and in total (n = 127) from 50 +/- 1 to 52.5 +/- 1% (p < .001). In addition, PF incubation of sperm samples resulted in higher sperm motility values compared to swim-up in all categories of sperm samples. Furthermore, progressive motility increased in all sperm groups following PF treatment (astheno-spermic: +16.7%; oligoasthenospermic: +14%, p < .001; oligozoospermic: +23.5%, p < .001; normozoospermic: +15.3%, p < .05; total +19.2%, p < .001). Sperm preparation with PF resulted in higher fertilization rates in all categories of sperm samples compared to swim-up (total: 46.6 vs. 29.1%, respectively; p < .05). Moreover, PF treatment of human sperm resulted in 9 viable pregnancies (IVF/ET: 5, AIH/IUI: 4) and one biochemical (IVF/ET). PF improving sperm motility and fertilizing capacity appears to be a promising motility stimulant.

Advanced methods for evaluation of sperm quality

Routine semen analysis includes measurements of sperm concentration, motility, and morphology. In our study, three additional tests were evaluated in relation to fertilization rate in an in vitro fertilization program: the freezing and hypo-osmotic swelling tests that evaluate the functional integrity and stability of the sperm membrane under extreme osmotic conditions, and migration sedimentation test that isolates high-quality motile sperm cells. The study was performed on semen delivered by men of couples treated at the In Vitro Fertilization Unit, and men who served as semen donors (fresh or cryopreserved semen). No correlation was found between the sperm fertilization rate, and the decrease in motility percent following the freezing-thawing process. Thus, the freezing test cannot be used to predict semen fertilization capacity. The hypo-osmotic swelling test was applied on semen given by a similar population of men. While the hypo-osmotic swelling test values carried out with fresh semen was found to have good correlation with fertilization, no correlation was found when frozen thawed semen was used. Post-migration sedimentation test sperm characteristics, and especially the recovery rate of the motile sperm, were significantly better in in vitro fertilization cycles with fertilizations. Both the hypo-osmotic swelling test and migration sedimentation test can assist in evaluating semen quality, judged by the fertilization rate in an in vitro fertilization program.

Effect of pentoxifylline on experimentally induced lipid peroxidation in human spermatozoa

We demonstrated previously that pentoxifylline in millimolar concentrations can inhibit superoxide anion production by human spermatozoa. In the present study we have examined the effects of the same concentrations of pentoxifylline on experimentally induced lipid peroxidation, as measured by malondialdehyde formation in the thiobarbituric (TBA) assay. Under the experimental conditions used, preincubation of spermatozoa with pentoxifylline led to a significant dose-dependent stimulation (p < 0.005) of malondialdehyde production amounting to 10.77 +/- 2.35%, 13.45 +/- 2.99% and 17.4 +/- 1.99% (mean +/- SEM) for 1.9, 3.7 and 11.2 mmol/l pentoxifylline, respectively. In the presence of 11.2 mmol/l pentoxifylline, an increase in iron-catalysed lipid peroxidation potential was detected in samples of spermatozoa from 29 infertile men, regardless of their initial levels of malondialdehyde. The results of this study indicate that pentoxifylline might further augment the ferrous ion-stimulated decomposition of pre-accumulation lipid hydroperoxides in the sperm plasma membrane and thus promote malondialdehyde generation in the TBA assay. It is concluded that the stimulatory effect of pentoxifylline on iron-induced lipid peroxidation may have an adverse effect on the quality of sperm suspensions prepared for in vitro fertilization, a possibility which should be investigated further.

Effects of pentoxifylline on human sperm parameters in vitro

PURPOSE

Pentoxifylline was tested in three raising concentrations (0.7 mM/l, 1.5 mM/l, 3.6 mM/l) on human sperm cells in vitro.

METHODS

On 143 samples, we examined drug effect on motile sperm concentration, grade of their motility, acrosome reaction and membrane status.

RESULTS

Obtained results show improvement in motile sperm concentration, as well as in the grade of progression in the majority of samples.

CONCLUSIONS

Spermatozoa membranes as well as occurrence of the acrosomal reaction were not affected by pentoxifylline.

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.

Pentoxifylline acts synergistically with A23187 to increase the penetration of zona-free hamster oocytes by cryopreserved human spermatozoa

The number of cryopreserved human spermatozoa which penetrated zona-free hamster oocytes after stimulation with 2 mumol A23187 per litre was increased by the further addition of 0.6 or 3.6 mmol pentoxifylline per litre. With spermatozoa prepared by washing by repeated centrifugation, the median numbers of sperm heads/egg were 1.9, 7.9 and 10.8 in the presence of 0, 0.6 or 3.6 mmol pentoxifylline per litre, respectively. A similar effect was observed with spermatozoa prepared on a Percoll gradient. As A23187 inhibited sperm motility, and this was exacerbated by pentoxifylline, the increased penetration rate of hamster oocytes cannot be explained by improved sperm motility. The number of spermatozoa stimulated to acrosome react by 2 mumol A23187 per litre was increased 3-fold by 3.6 mmol pentoxifylline per litre and 4-fold by 5 mmol caffeine per litre. These data suggest that cAMP may act synergistically with Ca2+ to stimulate the acrosome reaction. Pentoxifylline may improve the fertility of poor-quality human spermatozoa by enhancing their ability to respond to the Ca2+ signal produced by binding to the zona pellucida.

Cryopreservation of microsurgically extracted ductal sperm: pentoxifylline enhancement of motility

Microscopically extracted ductal sperm can be successfully cryopreserved using motility as the outcomes measure. The optimal regimen for cryopreservation of microscopically extracted ductal sperm awaits further determination. Pentoxifylline treatment improves initial post-thaw motility of cryopreserved microscopically extracted ductal sperm. The clinical efficacy of this practice awaits further determination. However, the best potential use for cryopreserved microscopically extracted ductal sperm may be IVF with subzonal or intracytoplasmic microinjection. If intracytoplasmic sperm injection becomes more widely available, then enhancement of motility with pentoxifylline may not be necessary. This approach allows for potential fertility insurance at the time of microsurgical bypass of obstruction, and it may preclude, the need for the andrologic surgeon to accurately time his sperm retrieval procedures with IVF. The latter potential advantage would significantly aid current logistical difficulties in the operating room.

Variability of the response to pentoxifylline in vitro in infertile normozoospermic and asthenozoospermic patients

The in vitro effect on the motility of spermatozoa of the methylxanthine pentoxifylline was studied in 30 patients consulting for infertility (13 normozoospermic and 17 asthenozoospermic). After separation by centrifugation on Percoll gradient, the spermatozoa were incubated for 30 min in pentoxifylline (3.6 mM), then the pentoxifylline was removed by washing and centrifugation. The residual effect of pentoxifylline was studied by computer-assisted videomicrographic analysis of the sperm motion parameters. In both groups of patients a decrease in the percentage of motile spermatozoa after exposure to pentoxifylline was observed, as compared with a control group. The effect on the motion parameters varied according to the time of observation (30, 120, 240 min). In the asthenozoospermic patients, the curvilinear velocity (VCL) was not modified in a statistically significant manner. In the normozoospermics, the VCL was increased after exposure to pentoxifylline at 120 min (p = .03) and 240 min (p = 10(-5)); similarly, the amplitude of the lateral head displacement (ALH) was greater in this group at 120 and 240 min (p = .01 for maximum ALH). However, a heterogeneity was noted in the response between individuals, which required that the statistical analyses take into account these differences.

Oral pentoxifylline in therapy-resistant idiopathic OAT syndrome

After previous treatment failure using tamoxifen either alone or in combination with kallikrein, 25 patients with idiopathic oligoasthenoteratozoospermia (OAT syndrome) were subjected to 3 months of treatment with pentoxifylline at a dosage of 1200 mg/day. The only statistically significant (p < .008) improvement detected in the post-therapeutic spermiograms was an increase of normal forms. All other ejaculate parameters (density, motility, swelling test, penetration test) remained unchanged, and there was only one post-therapeutic pregnancy. It would appear the pentoxifylline after failure of established treatment modalities is not a therapy of choice in idiopathic OAT syndrome.

Persistent effects of pentoxifylline on human sperm motility, after drug removal, in normozoospermic and asthenozoospermic individuals

The aim of the study was to compare the in vitro effect of pentoxifylline on human sperm motility when added prior to sperm selection and the persistence of the response after drug removal in normo- and asthenozoospermic individuals. The sperm samples were obtained from 22 men who were repeatedly asthenozoospermic or normozoospermic. Sperm movement was measured using computer-assisted semen analysis over 180 min. Percentage motility and progressive motility were increased in both normo- and asthenozoospermic samples (P < 0.05). Curvilinear velocity, amplitude of lateral head displacement and beat-cross frequency were increased in both groups (P < 0.05). Straight-line velocity was increased significantly in the normozoospermic group only. In both normo- and asthenozoospermic individuals pentoxifylline appeared to enhance sperm motility for at least 180 min after drug removal. This should prevent any potentially toxic effects of the drug on oocytes if it is used to enhance sperm motility during in vitro fertilization.

Use of the acrosome reaction to ionophore challenge test in managing patients in an assisted reproduction program: a prospective, double-blind, randomized controlled study

OBJECTIVE

To assess the utility of the acrosome reaction (AR) to ionophore challenge test in determining the sperm treatment protocols for patients undergoing assisted reproduction.

DESIGN, SETTING, PATIENTS

One hundred twenty-one couples undergoing an IVF-ET or GIFT procedure from January to July 1992 were included in this prospective study. All cases had a preliminary semen analysis within the previous 3 months and an AR to ionophore challenge test was carried out unless an acceptable fertilization rate occurred on previous IVF. For those patients whose AR to ionophore challenge score was below the accepted fertile range of > or = 10%, a second AR to ionophore challenge test was performed after exposure of sperm to the stimulant pentoxifylline. Couples then were managed by assisted reproduction with randomized allocation of oocytes for fertilization with a standard sperm preparation or with added sperm stimulants, either 3.6 mM pentoxifylline alone or combined with 3.0 mM 2-deoxyadenosine. The study was double-blind with neither the patients nor the embryologist knowing the AR to ionophore challenge result at the time of the IVF procedure.

MAIN OUTCOME MEASURES

Data from the preliminary semen analyses and AR to ionophore challenge scores were correlated with the fertilization rates achieved using control and treated sperm preparations. The rates of total fertilization failure and the numbers of clinical pregnancies occurring in each subgroup were also recorded.

RESULTS

All AR to ionophore challenge groups showed normal sperm counts except the groups with poor AR to ionophore challenge, which demonstrated reduced sperm counts. The group with normal AR to ionophore challenge scores or previous normal fertilization showed satisfactory fertilization rates with either control or treated sperm, although some individual cases showed reduced fertilization with treated sperm. The fertilization rate for the group with low AR to ionophore challenge scores improved significantly with pentoxifylline, and the benefit was greatest when this had been predicted from the AR to ionophore challenge studies. Cases with persisting poor AR to ionophore challenge despite pentoxifylline showed no significant improvement in fertilization rates with sperm exposed to either sperm stimulant regimens. Poor AR to ionophore challenge scores were also predictive of total fertilization failure, but this problem was reduced by sperm stimulation. The AR to ionophore challenge score at 10% cutoff level showed optimal levels of sensitivity (82.1%), highest negative predictive value (82.1%), and lowest false negative rate (17.9%).

CONCLUSIONS

The AR to ionophore challenge test is useful in the assessment and management of the male factor in assisted reproduction. It can be used to identify the majority of cases who will benefit from the use of sperm stimulants.

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.

Subzonal insemination (SUZI) or in vitro fertilization (IVF) in microdroplets for the treatment of male-factor infertility

PURPOSE

The results of subzonal insemination (SUZI) and in vitro fertilization with microdroplet insemination used in couples with male-factor infertility are presented.

RESULTS

The total fertilization rate was 17.4% for SUZI (n = 89) and 49.3% for microdroplet IVF (n = 100). The fertilization rate for standard IVF (n = 510), not including any male-factor infertility and performed during the same period, was 73.2%. The "take-home baby rate" per started cycle and per embryo transfer (ET), respectively, was 10 and 17.6% for SUZI and 20 and 24.7% for microdrop IVF. For standard IVF these figures were 27 and 31.7%.

CONCLUSION

It was concluded that microdroplet IVF can be used with good results in cases of moderate male-factor infertility. The normal (2PN) fertilization rate with the SUZI technique was only 15.1%. However, despite the low fertilization rate, SUZI should be considered when dealing with severe male-factor infertility.

Sperm function and its manipulation for microassisted fertilization

Comprehension of the intricate complexities of sperm function is clearly crucial to the success of attempts to manipulate it for the purposes of assisted conception. This is particularly important when considering various procedures for microassisted fertilization since these bypass critical physiological events that are mandatory for normal fertilization, to varying degrees. Methylxanthine derivatives such as pentoxifylline are useful agents for the management of oligoasthenozoospermic patients. This is particularly so for procedures such as SUZI where adequate motility of spermatozoa injected into the perivitelline space is crucial for fusion with the vitelline membrane to achieve fertilization. The generation of minute concentrations of reactive oxygen species in vitro may prove to be a valuable technique in this respect, in the light of recent evidence for their involvement in capacitation and hyperactivation. Induction of the acrosome reaction by non-invasive, non-toxic agents should markedly improve success rates for microassisted fertilization. Acrosin appears to play a central role in this and, therefore, it would seem prudent to monitor levels of acrosin activity in samples of spermatozoa used in assisted conception procedures. With respect to microassisted fertilization, the potential to select recently acrosome-reacted spermatozoa coated by activated acrosin promises to be a major improvement. Current methods employed for determination of the fertilization potential of spermatozoa are clearly inadequate (Polansky and Lamb, 1988; Aitken, 1990). In fact, the prevailing evidence suggests that no single parameter of sperm function reflects this potential (Zaneveld and Jeyendran, 1988). Therefore, we have both a scientific and a moral responsibility to investigate these processes further. Subsequently, we should be in a position to identify individual gametes with the potential for fertilization and so utilize procedures that result in maximal fertilization rates with minimal risk of polyploidy or abnormality.

The influence of pentoxifylline on motility and viability of spermatozoa from normozoospermic semen samples

In order to evaluate the effects of pentoxifylline on sperm motility and longevity, a controlled in-vitro study was conducted on normozoospermic donor semen samples using the Cellsoft automated system for sperm motility analysis. After incubation and selection, pentoxifylline was found to improve the recovery of spermatozoa and to increase their velocity. In the subgroup of progressively motile spermatozoa, curvilinear velocity was also enhanced. It is concluded that pentoxifylline has an effect on the vigour, but not on the pattern, of sperm motion. Pentoxifylline did not improve the motility characteristics of senescent spermatozoa in normozoospermic sperm samples. Sperm survival, as shown by supra-vital staining, and motility longevity both decreased with time after pentoxifylline treatment.

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.