Cryopreservation of microsurgically extracted ductal sperm: pentoxifylline enhancement of motility

Does in vitro application of pentoxifylline have beneficial effects in assisted male reproduction?

Application of nonspecific phosphodiesterases inhibitors, such as pentoxifylline (PTX), is a strategy utilised to aid sperm selection from immotile sperm samples prior to ICSI. No extensive studies have yet been performed to verify the safety of the clinical outcomes of ICSI after PTX administration. In this article, we summarise the data reported in the literature that assess the implication of in vitro usage of PTX on sperm parameters, as well as clinical outcomes during assisted male reproduction programme.

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.

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.

Factors associated with the quality before freezing and after thawing of sperm obtained by microsurgical epididymal aspiration

OBJECTIVE

To identify whether the cause, site of ductal obstruction, and characteristics of fluid aspirates are associated with the cryosurvival and fertility after thawing of sperm obtained during reconstruction of the excurrent ducts with microsurgical epididymal sperm aspiration, vasal sperm aspiration, or both.

DESIGN

Prospective study.

SETTING

Andrology center at a tertiary care institution.

PATIENT(S)

Men undergoing reconstruction of the excurrent duct and sperm aspiration (n = 42) or microsurgical epididymal sperm aspiration (n = 11).

INTERVENTION(S)

Sperm were tested for an association with the cause and site of obstruction. Fertilization and pregnancy rates after sperm aspiration and intracytoplasmic sperm injection (ICSI) were evaluated for fresh and frozen aspirates.

MAIN OUTCOME MEASURE(S)

Motile sperm count and percentage motility after thawing.

RESULT(S)

The motile sperm count before freezing was significantly higher in the caput epididymis than in the corpus. The motile sperm count before freezing was related inversely to the distance from the caput where the sperm were aspirated. Sperm from clear and opaque fluid aspirates had better percent motility than those from cloudy and creamy fluid aspirates. High fertilization and pregnancy rates were achieved using both fresh and frozen epididymal sperm.

CONCLUSION(S)

None of the factors studied was associated with cryosurvival of aspirated epididymal or vasal spermatozoa. Because motility is low after thawing, these specimens are best used with ICSI.

Effect of level of anastomosis and quality of intraepididymal sperm on the outcome of end-to-side epididymovasostomy

OBJECTIVES

Epididymovasostomy is commonly performed at the most distal site of the epididymis where whole sperm are present within the lumen, regardless of their motility status. Although more fresh and motile sperm can be found more proximally within the epididymis, it is believed that the outcome of epididymovasostomy is better more distally. Because the current results of epididymovasostomy are far from perfect, it would be ideal to be able to harvest motile sperm for cryopreservation at the time of surgery in case the patient remains azoospermic postoperatively. The objective of this study was to determine the effect of the level of epididymal anastomosis and quality of sperm on the outcome of surgery.

METHODS

An end-to-side epididymovasostomy was performed on 131 azoospermic men with a mean age of 39 years and a mean obstructive interval of 18 years. The etiology of obstruction was vasectomy in 48%, infectious in 19%, congenital in 20%, and unknown in 13%. The average duration of follow-up was 32 months. The overall patency rate was 67% and pregnancy rate was 27%. Subgroups of patients with an anastomosis to the same level of the epididymis on all functional sides were identified as follows: caput (56), corpus (28), and cauda (13). These groups were compared in regard to the presence of motile sperm within the epididymal lumen at the time of surgery, patency rates, postoperative semen quality, and pregnancy rates.

RESULTS

Motile sperm were present more often in both the caput (54%) and corpus (61%) than in the cauda epididymis (25%) (P < 0.05). The patency rates for the three subgroups were not significantly different. The postoperative total motile sperm count and pregnancy rate for the corpus epididymis (13 x 10(6) and 45%) was significantly (P < 0.05) better than for the caput (4.4 x 10(6) and 22%) but no different than that of the cauda (10 x 10(6) and 23%). The patency and pregnancy rates for anastomoses performed at levels demonstrating motile sperm were not significantly better than at sites with nonmotile sperm, but the postoperative total motile sperm count was better (P < 0.05).

CONCLUSIONS

The results of this study suggest that the outcomes of epididymovasostomy to the corpus and cauda epididymis are roughly equivalent and superior to the caput. Therefore, it may be reasonable to move more proximally from the cauda to corpus in the search for motile sperm for cryopreservation during an end-to-side epididymovasostomy. In contrast, moving from the corpus to the caput epididymis has a significant adverse effect upon outcome; it is, therefore, not worthwhile to search for viable sperm for cryopreservation in this clinical setting.