Effect of sperm treatment with exogenous platelet-activating factor on the outcome of intrauterine insemination

The definition of unexplained infertility: A systematic review

BACKGROUND

There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice.

OBJECTIVES

This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis.

SEARCH STRATEGY

CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language.

DATA COLLECTION AND ANALYSIS

Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range.

MAIN RESULTS

Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies.

CONCLUSIONS

This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care.

Semen preparation techniques for intrauterine insemination

BACKGROUND

Semen preparation techniques for assisted reproduction, including intrauterine insemination (IUI), were developed to select the motile morphologically normal spermatozoa. The yield of many motile, morphologically normal spermatozoa might influence treatment choices and therefore outcomes.

OBJECTIVES

To compare the effectiveness of three different semen preparation techniques (gradient; swim-up; wash and centrifugation) on clinical outcomes (live birth rate; clinical pregnancy rate) in subfertile couples undergoing IUI.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group (CGFG) trials register, CENTRAL, MEDLINE, Embase, Science Direct Database, National Research Register, Biological Abstracts and clinical trial registries in March 2019, and checked references and contacted study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the efficacy in terms of clinical outcomes of semen preparation techniques used for subfertile couples undergoing IUI.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. The primary review outcomes are live birth rate and clinical pregnancy rate per couple.

MAIN RESULTS

We included seven RCTS in the review; we included six of these, totalling 485 couples, in the meta-analysis. No trials reported the primary outcome of live birth. The evidence was of very low-quality. The main limitations were (unclear) risk of bias, signs of imprecision and inconsistency in results among studies and the small number of studies/participants included.Swim-up versus gradient technique Considering the quality of evidence, we are uncertain whether there was a difference between clinical pregnancy rates (CPR) for swim-up versus a gradient technique (odds ratio (OR) 0.83, 95% CI 0.51 to 1.35; I² = 71%; 4 RCTs, 370 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a gradient technique is assumed to be 24%, the chance of pregnancy after using the swim-up technique is between 14% and 30%. We are uncertain whether there was a real difference between ongoing pregnancy rates per couple (OR 0.39, 95% CI 0.19 to 0.82; heterogeneity not applicable; 1 RCT, 223 participants; very low-quality evidence). Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates (MPR) per couple comparing a swim-up versus gradient technique (MPR per couple 0% versus 0%; 1 RCT, 25 participants; very low-quality of evidence). Considering the quality of evidence, we are also uncertain whether there was a difference between miscarriage rates (MR) per couple comparing a swim-up versus gradient technique (OR 0.85, 95% CI 0.28 to 2.59; I² = 44%; 3 RCTs, 330 participants; very low-quality evidence). No studies reported on ectopic pregnancy rate, fetal abnormalities or infection rate.Swim-up versus wash techniqueConsidering the quality of evidence, we are uncertain whether there is a difference in clinical pregnancy rates after a swim-up technique versus wash and centrifugation (OR 0.41, 95% CI 0.15 to 1.13; I² = 55%; 2 RCTs, 78 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a wash technique is assumed to be 38%, the chance of pregnancy after using the swim-up technique is between 9% and 41%. Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates between swim-up technique versus wash technique (OR 0.49, 95% CI 0.02 to 13.28; heterogeneity not applicable; 1 RCT, 26 participants; very low-quality evidence). Miscarriage rate was only reported by one study: no miscarriages were reported in either treatment arm. No studies reported on ongoing pregnancy rate, ectopic pregnancy rate, fetal abnormalities or infection rate.Gradient versus wash techniqueConsidering the quality of evidence, we are uncertain whether there is a difference in clinical pregnancy rates after a gradient versus wash and centrifugation technique (OR 1.78, 95% CI 0.58 to 5.46; I² = 52%; 2 RCTs, 94 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a wash technique is assumed to be 13%, the chance of pregnancy after using the gradient technique is between 8% and 46%. Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates per couple between the treatment groups (OR 0.33, 95% CI 0.01 to 8.83; very low-quality evidence). Considering the quality of evidence, we are also uncertain whether there was a difference between miscarriage rates per couple between the treatment groups (OR 6.11, 95% CI 0.27 to 138.45; very low-quality evidence). No studies reported on ongoing pregnancy rate, ectopic pregnancy rate, fetal abnormalities or infection rate.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend any specific semen preparation technique: swim-up versus gradient versus wash and centrifugation technique. No studies reported on live birth rates. Considering the quality of evidence (very low), we are uncertain whether there is a difference in clinical pregnancy rates, ongoing pregnancy rates, multiple pregnancy rates or miscarriage rates per couple) between the three sperm preparation techniques. Further randomised trials are warranted that report live birth data.

Techniques used for IUI: is it time for a change?

STUDY QUESTION

Are the guidelines for the technical aspects of IUI (WHO, 2010) still in accordance with the current literature?

SUMMARY ANSWER

In general, the laboratory guidelines of the World Health Organization (WHO) are a suitable protocol, although the evidence is not always conclusive and some changes are advisable.

WHAT IS KNOWN ALREADY

Lack of standardization of the technical procedures required for IUI might result in inter-laboratory variation in pregnancy rates. Most centers still use their own materials and methods even though some guidelines are available.

STUDY DESIGN, SIZE, DURATION

A structural review focusing on the association between pregnancy rates and the procedures of semen collection (e.g. ejaculatory abstinence, collection place), semen processing (e.g. preparation method, temperature during centrifugation/storage), insemination (e.g. timing of IUI, bed rest after IUI) and the equipment used.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A literature search was performed in Medline and the Cochrane library. When no adequate studies of the impact of a parameter on pregnancy results were found, its association with sperm parameters was reviewed.

MAIN RESULTS AND THE ROLE OF CHANCE

For most variables, the literature review revealed a low level of evidence, a limited number of studies and/or an inadequate outcome measure. Moreover, the comparison of procedures (i.e. semen preparation technique, time interval between semen, collection, processing and IUI) revealed no consensus about their results. It was not possible to develop an evidence-based, optimal IUI treatment protocol.

LIMITATIONS, REASONS FOR CAUTION

The included studies exhibited a lack of standardization in inclusion criteria and methods used.

WIDER IMPLICATIONS OF THE FINDINGS

This review emphasizes the need for more knowledge about and standardization of assisted reproduction technologies. Our literature search indicates that some of the recommendations in the laboratory guidelines could be adapted to improve standardization, comfort, quality control and to cut costs.

STUDY FUNDING/COMPETING INTEREST(S)

The Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), Nijmegen, The Netherlands. S.K. and W.N. have no conflicts of interest to disclose. C.B. and A.W. are members of the board of the SKML. With a grant from SKML, L.L. was paid for her time to perform the research and write the publication. D.B. received grants from Merck Serono, Ferring and MSD, outside the submitted work.

REGISTRATION NUMBER

N/A.

Semen quality and prediction of IUI success in male subfertility: a systematic review

Many variables may influence success rates after intrauterine insemination (IUI), including sperm quality in the native and washed semen sample. A literature search was performed to investigate the threshold levels of sperm parameters above which IUI pregnancy outcome is significantly improved and/or the cut-off values reaching substantial discriminative performance in an IUI programme. A search of MEDLINE, EMBASE and Cochrane Library revealed a total of 983 papers. Only 55 studies (5.6%) fulfilled the inclusion criteria and these papers were analysed. Sperm parameters most frequently examined were: (i) inseminating motile count after washing: cut-off value between 0.8 and 5 million; (ii) sperm morphology using strict criteria: cut-off value ⩾5% normal morphology; (iii) total motile sperm count in the native sperm sample: cut-off value of 5-10 million; and (iv) total motility in the native sperm sample: threshold value of 30%. The results indicate a lack of prospective studies, a lack of standardization in semen testing methodology and a huge heterogeneity of patient groups and IUI treatment strategies. More prospective cohort trials and prospective randomized trials investigating the predictive value of semen parameters on IUI outcome are urgently needed. It is generally believed that intrauterine insemination (IUI) with homologous semen should be a first-choice treatment to more invasive and expensive techniques of assisted reproduction in cases of cervical, unexplained and moderate male factor subfertility. The rationale for the use of artificial insemination is to increase gamete density at the site of fertilization. Scientific validation of this strategy is difficult because literature is rather confusing and inconclusive. Many variables may influence success rates after IUI treatment procedures. It seems logical that sperm quality has to be one of the main determinants to predict IUI success. Clinical practice would benefit from the establishment of threshold levels for sperm parameters above which IUI pregnancy outcome is significantly improved and below which a successful outcome is unlikely. We performed a literature search to investigate if such threshold levels are known. Most striking were the lack of standardization in semen-testing methodology and the huge heterogeneity of patient groups and IUI treatment strategies. The four sperm parameters most frequently examined were: (i) inseminating motile count after washing: cut-off value between 0.8 and 5 million; (ii) sperm morphology using strict criteria: cut-off value >4% normal morphology; (iii) total motile sperm count in native sperm sample: cut-off value of 5-10 million; and (iv) total motility in native sperm sample: threshold value of 30%. This review identified an urgent need for more and better prospective cohort trials investigating the predictive value of semen parameters on IUI pregnancy rate.

Clinical significance and expression of PAF and TNF-alpha in seminal plasma of leukocytospermic patients

Objective. Discuss the changes and roles of PAF in the reproductive tract infection by observing the expression of platelet activating factor (PAF) and tumor necrosis factor α (TNF-α) in seminal plasma of patients with leukocytospermia. Methods. The seminal plasma was obtained from 22 cases of leukocytospermia and 15 cases of normal males; the peroxidase dyeing method was adopted for seminal plasma white blood count; the ELISA was adopted to test PAF and TNF-α concentration in seminal plasma. Result. PAF concentration (2.14 ± 0.43 ng/mL) of leukocytospermia group was significantly lower than the normal group (6.21 ± 1.38 ng/mL, P < 0.01) while TNF-α (5.51 ± 1.46 ng/mL) was significantly higher than that of normal group (3.48 ± 1.08 ng/mL). There was negative correlation between PAF and TNF-α , (r = −0.68, P < 0.01); the same situation existed in PAF and WBC (r = −0.62, P < 0.01); but TNF-α was positively correlated to WBC (r = 0.77, P < 0.01). Conclusion. (1) Low expression of PAF and high expression of TNF-α in leukocytospermia affect the sperm motility, which is one of the reasons that leads to infertility. (2) Lower expression of PAF has its particularity during the reproductive tract infection.

Exogenous platelet-activating factor improves the motility of human spermatozoa evaluated with C.A.S.A.: optimal concentration and incubation time

The objective of this study is to determine the optimal conditions for human semen incubation treated with exogenous platelet activating factor (ePAF) for intra-uterine insemination (IUI). This prospective study was carried out on 32 infertile men and each semen sample was processed with the ISolate Sperm Separation Medium, washed with sperm washing medium (SWM) and resuspended either in SWM alone (control samples), or with ePAF 0.1, 0.5, and 1.0 μM. Each concentration was subsequently incubated and evaluated at 5, 15, 30, and 60 min. The motility parameters were evaluated by the computer-aided sperm analysis (C.A.S.A.) system. Curvilinear velocity, straight line velocity, average path velocity, rapid and progressive motility significantly increased compared to control samples at an ePAF concentration of 0.1 μM (with at least 15 min of incubation). The best results were obtained with ePAF concentrations of: 0.1 μM (60 min of incubation) and 0.5 μM (30-60 min of incubation). In conclusion, results are enhanced when ePAF is added to standard semen preparation for IUI. An ePAF concentration of 0.1 μM, with an incubation time of 15 min, can be used for semen samples with normal motility. Whilst, for semen samples with poor motility, the ePAF concentration is best increased to 0.5 μM and/or the incubation time prolonged to 60 min.

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 as possible might influence treatment choices and therefore outcomes.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group Trials Register (13 January 2007), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to January 2007 ), EMBASE (1980 to January 2007), Science Direct Database (1966 to January 2007), National Research Register (2000 to 2007), Biological Abstracts (2000 to January 2007), CINAHL (1982 to October 2006) and reference lists of relevant articles. We also contacted experts and authors in the field.

SELECTION CRITERIA

Parallel randomized controlled trials (RCTs) comparing the efficacy of semen preparation techniques used for subfertile couples undergoing IUI in terms of clinical outcome were included.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Five RCTs, including 262 couples in total, were included in the meta-analysis (Dodson 1998; Grigoriou 2005; Posada 2005; Soliman 2005; Xu 2000). Xu compared the three techniques; Soliman compared a gradient technique versus a wash technique; Dodson and Posada compared a gradient technique versus a swim-up technique; whereas Grigoriou compared swim-up versus a wash technique. No trials reported the primary outcome of live birth. There was no evidence of a difference between pregnancy rates (PR) for swim-up versus a gradient or wash and centrifugation technique (Peto OR 1.57, 95% CI 0.74 to 3.32; Peto OR 0.41, 95% CI 0.15 to 1.10, respectively); nor in the two studies comparing a gradient technique versus wash and centrifugation (Peto OR 1.76, 95% CI 0.57 to 5.44). There was no evidence of a difference in the miscarriage rate (MR) in two studies comparing swim-up versus a gradient technique (Peto OR 0.13, 95% CI 0.01 to 1.33).

AUTHORS' 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.

Essential role of platelet-activating factor in male reproduction: a review

The use of pharmacological adjuvants to enhance sperm function is a real possibility and a very attractive proposition. However, the role of such adjuvants must be well defined to maximize therapeutic outcome for specific patient populations. Platelet-activating factor (PAF) is a potent signalling phospholipid that has been implicated in a number of biological activities. In the field of reproductive biology, PAF has been shown to have an important role in ovulation, sperm function, embryo implantation, fetal lung maturation, and initiation and maintenance of parturition. Although the exact mechanisms are not clear, it has been demonstrated in several species that PAF can influence sperm function by affecting the motility, capacitation, acrosome reaction and fertility of spermatozoa. The reproductive significance of PAF activity in spermatozoa and fertilization and its role in the establishment of pregnancy requires further study. Understanding the role of PAF in a reproductive process, such as in intrauterine insemination, could eventually lead researchers to explore its role in more complex reproductive technologies. This review summarizes the current research on the significant role of PAF in male mammalian reproductive functions, as well as its possible application in some assisted reproductive technologies.