Comparison of techniques for the selection of bacteria-free sperm preparations

Sperm selection using single layer centrifugation prior to cryopreservation can increase thawed sperm quality in stallions

REASONS FOR PERFORMING STUDY

The increasing use of modern reproductive techniques in human medicine has led to a higher demand for isolation of motile sperm. Several of these isolation techniques have been adapted for veterinary use and can be applied for the selection of a superior sperm sample from stallion semen. Until recently a major disadvantage of such isolation techniques was the limitation in sperm volume that could be handled. Androcoll-E had been shown to be successful for processing large volumes of equine semen but there are few data to substantiate the potential beneficial effect of freezing an Androcoll-E selected equine sperm sample to obtain higher quality following thawing.

OBJECTIVES AND METHODS

In this study, the effect of Androcoll-E treatment of sperm prior to cryopreservation was compared with cushioned centrifugation using ejaculates from 8 different stallions selected because they were known to have semen of differing quality following freezing.

RESULTS

Androcoll-E treatment increased measures of semen quality prior to freezing. However, Androcoll-E treatment reduced the yield of sperm following centrifugation when compared with the cushion centrifuged control group (50.9 ± 14.2% vs. 97.1 ± 9.0%, respectively). Quality analysis following thawing showed an overall improved sperm quality for Androcoll-E treated samples and average post thaw progressive motility (PM) was 41.6% compared with 30.5% for the cushion centrifuged group.

CONCLUSIONS AND POTENTIAL RELEVANCE

Androcoll-E can be used with good results to select a superior sperm population prior to cryopreservation, in order to produce good-quality frozen thawed semen.

Semen preparation techniques for intrauterine insemination

BACKGROUND

Semen preparation techniques for assisted reproduction, including intrauterine insemination (IUI), were developed to separate the motile morphological normal spermatozoa. Leucocytes, bacteria and dead spermatozoa produce oxygen radicals that negatively influence the ability to fertilize the egg. The yield of as many motile, morphologically normal spermatozoa might influence treatment choices and therefore outcomes.

OBJECTIVES

To compare the effectiveness of gradient, swim-up, or wash and centrifugation in subfertile couples undergoing intrauterine insemination (IUI) on clinical outcome as well as on semen parameters.

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group's trials register (30 June 2003), MEDLINE (1966 to July 2003), EMBASE (1980 to July 2003), Science Direct Database (1966 to July 2003), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003), National Research Register (2000 to Issue 2, 2003), Biological Abstracts (2000 to June 2003), CINAHL (1982 to July 2003) and reference lists of relevant articles. We also contacted experts and authors in the field.

SELECTION CRITERIA

Parallel randomised controlled trials (RCTs), comparing the efficacy of semen preparation techniques used for subfertile couples undergoing IUI, were included. RCTs or split sample studies examining semen parameters after different semen preparation techniques were also included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Two randomised controlled trials comparing clinical outcomes, including 81 participants in total, were included in the meta-analysis (Dodson 1998-I/ II; Xu 2000-I/ II). Both studies compared swim-up technique versus gradient technique in 65 subfertile couples undergoing IUI. One study compared the effectiveness of both techniques with wash technique. No trials reported the primary outcome of live birth. There was no statistically significant difference between pregnancy rates (PR) for swim-up versus gradient / wash centrifuge (Peto OR 0.55, 95% CI 0.17 to 1.76; Peto OR 1.74, 95% CI 0.2 to 14.9; PR/ couple swim-up 20%, gradient 40%, wash 12.5%) or gradient versus wash centrifuge (Peto OR 4.01, 95% CI 0.82 to 19.56; PR/ couple swim-up 15%, gradient 20%). There was no significant difference in the miscarriage rate (MR) per couple between either of the three treatment groups in the one trial reporting this outcome (MR/ couple swim-up 0%, gradient 10.3%, wash 0%. MR/ pregnancy gradient 30.3%). There was no statistically significant difference in the multiple pregnancy rate (MPR) per couple between either of the three treatment groups in Dodson 1998-I/ II (MPR/ couple swim -up 0%, gradient 0%, wash 6.3%). One triplet pregnancy was recorded. Fifteen studies comparing semen parameters after processing were included. Two studies were included in the meta-analysis, we were not able to pool results.

REVIEWERS' CONCLUSIONS

There is insufficient evidence to recommend any specific preparation technique. Large high quality randomised controlled trials, comparing the effectiveness of a gradient and/ or a swim-up and/ or wash and centrifugation technique on clinical outcome are lacking. Further randomised trials are warranted. Results from studies comparing semen parameters may suggest a preference for gradient technique, but firm conclusions cannot be drawn and the limitations should be taken into consideration.

Processing of semen in an antibiotic-rich culture medium to minimize microbial presence during in vitro fertilization

OBJECTIVE

To identify and determine the prevalence of microorganisms in preprocessed and postprocessed semen in an IVF-ET program.

DESIGN

Prospective study.

SETTING

University Teaching Hospital.

PATIENT(S)

Seventy-four men undergoing preprogram evaluation, each producing two semen samples.

INTERVENTION(S)

Semen processing with a wash and swim-up technique in a penicillin- and streptomycin-rich medium.

MAIN OUTCOME MEASURE(S)

The identity and prevalence of seminal microorganisms before and after processing.

RESULT(S)

Sixty-three percent of individual unprocessed semen samples grew microorganisms, the majority of which were nonpathogenic. Thirty-three men (44.6%) had microbes identified in repeat samples, four had identical organisms each time. Twenty (27%) had positive cultures in one sample, negative in the other. Twenty-one (28.4%) had consistently sterile semen. After seminal processing, the recovery rate for microbes was 5%. Microbial presence after processing did not correlate with either the sperm swim-up concentration or the initial microbial concentration.

CONCLUSION(S)

Bacteriospermia is common. The microorganisms found rarely are replicated and most likely represent contamination. Wash and swim-up semen preparation in an antibiotic rich culture medium effectively eliminates 95% of organisms.

Variation in recovery of motile sperm after preparation by a simple Percoll gradient technique

PURPOSE

Numerous techniques have been used to prepare sperm for assisted reproduction technology. Density-gradient centrifugation with Percoll is becoming a method of choice. This study reviewed the results of a simple two-layer discontinuous Percoll gradient.

METHODS

We reviewed retrospectively results obtained from 208 semen specimens prepared for in vitro fertilization by a discontinuous Percoll gradient.

RESULTS

Overall results (mean +/- SD) were a recovery of 21 +/- 16% of total sperm, recovery of 38 +/- 30% of motile sperm, and a motility in the final sperm preparation of 88 +/- 10%. Specimens with higher initial concentrations had higher motility in the final preparation. Higher total recovery and higher motility in the final preparation were found for specimens with a higher initial motility.

CONCLUSIONS

This simple two-layer Percoll technique is rapid and inexpensive and reliably produces a final sperm preparation with desirable characteristics. Even though specimens with poor initial parameters yielded final preparations with excellent characteristics, fertilization rates were still related to the initial semen parameters.

Profiles of sperm morphology and motility after discontinuous multiple-step Percoll density gradient centrifugation

Morphology and motility are important parameters for assessing the fertilizing capacity of spermatozoa. This investigation reports a systematic study on the profiles of these parameters after percoll gradient centrifugation. Spermatozoa from normal human semen were fractionated by discontinuous Percoll gradients (30%, 45%, 75%, 90%). Spermatozoa washed with Earle's balanced salt solution were used as a control. After centrifugation, sperm morphology was evaluated according to strict criteria; motility was assessed by a computer-assisted semen analysis system. The results showed that the percentage of spermatozoa with normal morphology increased, while those with severe morphological defects decreased, as the density of Percoll increased. The percentages of motile spermatozoa and hyperactivated spermatozoa, and the velocity and amplitude of lateral head displacement of the spermatozoa were significantly higher in the 75% and 90% Percoll fractions than that in the 30% and 45% ones, and in the control. These results demonstrated that Percoll density gradient centrifugation enriched spermatozoa in terms of morphology and motility.

Techniques for selection of normal-chromatin sperm preparations

Various sperm preparation techniques, swim-up and Percoll gradient, and the newly developed Wang's tube system, were evaluated for their ability to recover normal-chromatin sperm. Twenty human semen samples, collected by masturbation, were studied simultaneously with the three methods. Analysis by Acridine orange fluorescence test was performed on all samples. Pretreated semen contains 58 +/- 22% green sperm (fertile/normal). Treatment with Wang's tube system resulted in 99 +/- 1.0% green sperm; Percoll gradient, 78 +/- 11%; and swim-up technique, 72 +/- 15%. It would appear that Wang's tube system yields a high-quality sperm preparation with enough concentration, very active forward progression, and greatly improved sperm morphology, while containing normal-chromatin, double-stranded DNA.

Fallopian replacement of eggs with delayed intrauterine insemination (FREDI): an alternative to gamete intrafallopian transfer (GIFT)

This report contains details of what is the first group of patients with nontubal infertility to undergo fallopian replacement of eggs with delayed intrauterine insemination (FREDI). Twenty-three patients suffering from idiopathic or immune infertility, polycystic ovarian disease (PCOD), or mild endometriosis underwent follicular stimulation with human menopausal gonadotropin and/or pure follicle-stimulating hormone plus human chorionic gonadotropin prior to laparoscopic pickup of eggs of varying maturity. Eggs without spermatozoa were transferred at the time of laparoscopy. Subsequent high intrauterine insemination (IUI) of washed spermatozoa at a time when egg maturation within the tubes was judged to be complete enabled a cohort of fully capacitated spermatozoa to meet fully mature eggs in a totally physiological manner. Eight clinical pregnancies arose from this group, one healthy, male infant has been delivered, and four pregnancies remain ongoing. Although based on a small population of patients, it does seem that in vivo egg maturation following replacement in the fallopian tube is an effective alternative to in vitro maturation and, with the increased control over timing of egg insemination, leads us to propose FREDI as a flexible new therapeutic approach for the treatment of nontubal infertility.

Artificial insemination with husband's sperm (AIH): techniques for sperm selection

Artificial insemination with husband's sperm (AIH) attempts to treat infertile couples by solving their particular infertility problems. This review is concerned with detailing and evaluating the experiences of different authors with AIH in infertile couples, types of insemination, and indications for insemination, with emphasis on techniques for sperm selection and separation: glass-wool filtration, separation on albumin columns, washed sperm, swim-up method, and spermatozoa selection in Percoll gradients.