Determinant Factors for Ongoing Pregnancy in Homologous Intrauterine Insemination Cycles - A Prospective Study.

BACKGROUND/AIM: Intrauterine insemination (IUI) is the most common assisted-reproduction treatment. However, it has lower success rate in comparison to other treatments. Therefore, determining factors that contribute to IUI success is of particular interest and this was the purpose of this prospective study. PATIENTS AND METHODS: In this study, only homologous inseminations with fresh semen samples were included. All women received mild ovarian stimulation with clomiphene citrate and gonadotropins. Before IUI, basic semen analysis, evaluation of DNA fragmentation index (DFI), as well as measurement of sperm redox potential, were performed on each semen sample. Semen was processed with density-gradient centrifugation and 500 µl of processed sperm was used for insemination. RESULTS: In 200 cycles, there were 36 pregnancies, six of them ectopic. Cycles with ongoing pregnancies were characterized by younger male and female age and higher number of follicles. Multivariate logistic regression analysis showed that only female age was significantly associated with ongoing pregnancy. DFI was positively correlated with male age and negatively correlated with sperm concentration and progressive motility. Semen redox potential showed a strong negative correlation with sperm concentration and positive correlation with DFI. CONCLUSION: Female age seems to be the most important determinant factor for the achievement of an ongoing pregnancy in homologous IUI cycles with fresh semen.

Culture of Human Embryos at High and Low Oxygen Levels.

One of the parameters potentially affecting the in vitro growth of preimplantation embryos is the oxygen concentration in the culture environment. An increased oxygen concentration causes the generation of ROS which in turn can cause damage to the cells and seriously disrupt the embryonic development. Previous studies have assessed oxygen concentrations in the fallopian tubes of several mammals of between 5 and 8%, while the oxygen levels in the uterus were found to be even lower; similar measurements have been confirmed in humans. In addition, studies in mammalian embryos showed that low oxygen concentrations improve embryo development. Multiple studies on the effect of the oxygen concentration on human embryos have been conducted so far with diverse methodologies and objectives. Data from these have been included in three meta-analyses. All meta-analyses indicate the potential benefit in favor of a low oxygen concentration, though data are considered to be of a low methodological quality and further studies are considered necessary. However, based on the existing evidence, it is suggested that a low oxygen concentration should be adopted in the routine of the IVF laboratory, especially in the case of blastocyst culture.

The Beneficial Effects of Pterostilbene on Post-Thawed Bovine Spermatozoa.

Reactive Oxygen Species (ROS), primarily produced by cellular metabolism, are highly reactive molecules that modify cellular compounds. During sperm preparation in Assisted Reproductive Techniques (ARTs), intrinsic and extrinsic sources of ROS can impact spermatozoa's oxidative status. The modification of the media with compounds that enhance sperm quality characteristics is of great significance. The current study investigated the effect of pterostilbene, a phenolic compound, on bovine sperm quality. Cryopreserved spermatozoa from six bulls were thawed, supplemented with pterostilbene (0, 10 µΜ, 25 µΜ) and incubated for 60 min and 240 min. Spermatozoa were analyzed in terms of motility, viability, acrosomal status and intracellular concentration of superoxide anion in each time point. The incubation of spermatozoa with 25 µΜ pterostilbene resulted in the preservation of quality parameters through superoxide anion mitigation, while its presence in capacitating conditions resulted in higher percentage of acrosome-reacted spermatozoa. The results of the present study indicate that the addition of pterostilbene prevents oxidative insult to spermatozoa and preserves the sperm quality parameters.

"You are my sunshine, my only sunshine": maternal vitamin D status and supplementation in pregnancy and their effect on neonatal and childhood outcomes.

Vitamin D (VD) plays a crucial role in regulating calcium homeostasis, while the wealth of its pleiotropic actions is gaining increasing research interest. Sufficient VD concentrations are of clinical relevance, particularly in the context of physiological alterations, such as those occurring during pregnancy when maternal VD is the sole source for the developing fetus. As a result, inadequate VD concentrations in pregnancy have been associated with perinatal complications and adverse neonatal outcomes, including preeclampsia, gestational diabetes mellitus, increased rates of cesarean section, low birth weight, small-for-gestational-age infants, poor immune and skeletal growth, allergies, and respiratory infections. Over the past few decades, several observational studies have underlined the important role of maternal VD in the neural, musculoskeletal, and psychomotor growth and bone health of the offspring. However, the complexity of the factors involved in regulating and assessing VD homeostasis, including race, sun exposure, dietary habits, and laboratory measurement techniques, makes the interpretation of relevant research findings challenging. The aim of this narrative review is to summarize the evidence on the importance of VD in maintaining optimal health during pregnancy, infancy, childhood, and adolescence.

Is There an Association Between Circulating Kisspeptin Levels and Ovarian Reserve in Women of Reproductive Age?

BACKGROUND/AIM: To investigate the possible association of kisspeptin levels with the ovarian reserves of women of reproductive age. PATIENTS AND METHODS: Eighty women aged 19-40 participated after signing an informed consent. Of these, 74 were finally included as in 6 women the blood samples were considered inappropriate due to hemolysis. They were divided into three main groups according to their ovarian reserve patterns: women with adequate ovarian reserves (Group A - AOR) (n=30), women with increased ovarian reserves (Group B - PCOS) (n=31), and women with diminished ovarian reserves (Group C - DOR) (n=13). RESULTS: Women with diminished ovarian reserves had statistically significantly increased age and FSH compared to the other two groups. No statistically significant difference was found between the three groups for estradiol and thyroid stimulating hormone. Moreover, body mass index, luteinizing hormone, total testosterone, 17-hydroxyprogesterone, dehydroepiandrosterone, anti-Mullerian hormone (AMH), and antral follicle count (AFC) were increased in group B compared to the other two groups. AMH and AFC were decreased in women with diminished ovarian reserves compared to the other two groups, as expected. The comparison of kisspeptin levels between the three groups showed that kisspeptin levels were increased in women with diminished ovarian reserves, compared to the other two groups, but without a statistically significant difference. However, kisspeptin levels in group C were statistically significantly higher than those in group A. CONCLUSION: There are no strong indications that kisspeptin levels are associated with the ovarian reserve in women of reproductive age.

Role of leptin, adiponectin, and kisspeptin in polycystic ovarian syndrome pathogenesis.

INTRODUCTION: Polycystic ovarian syndrome (PCOS) affects 5-20% of females and is the most common cause of anovulatory infertility. Leptin seems to have an important role in reproduction. Many reproductive pathologies such as preeclampsia, PCOS, and endometriosis are associated to plasma adiponectin levels. Kisspeptin levels are increased in PCOS women. EVIDENCE ACQUISITION: A review of the literature was completed through the PubMed database aiming to find articles regarding leptin, adiponectin and kisspeptin and if they are related to PCOS pathogenesis. EVIDENCE SYNTHESIS: Even today it is not clear what is the role of leptin in women with PCOS, although most of the researchers found increased levels of leptin as well as leptin resistance in PCOS (both obese and lean individuals). Many more longitudinal studies should be done to discover the usefulness of measuring adiponectin in prepubertal women who apparently have a possibility to develop PCOS to find out if they finally develop PCOS. Most of the researchers found that PCOS women have decreased levels of adiponectin unrelated to BMI levels. Nevertheless, not all studies had the same result. Moreover, it is necessary more studies to be made to investigate the connection between kisspeptin and other metabolic factors such as LH and insulin resistance. CONCLUSIONS: In general, it remains inconclusive whether leptin, adiponectin, and kisspeptin can be used as clinical and/or biochemical markers of PCOS. Therefore, it is essential to review the current data with regards to the association between PCOS and circulating leptin, adiponectin, and kisspeptin in women with PCOS.

Embryonic Cell-free DNA in Spent Culture Medium: A Non-invasive Tool for Aneuploidy Screening of the Corresponding Embryos.

BACKGROUND/AIM: Preimplantation genetic testing (PGT) for chromosomal screening, based on embryo biopsy, has significant limitations. Cell-free DNA (cf-DNA) has been detected in spent culture medium (SCM), opening new horizons for the development of non-invasive PGT (ni-PGT). In this study, we evaluated the diagnostic performance of ni-PGT for aneuploidy (niPGT-A), comparing the results of trophectoderm biopsies (TE) and respective SCM from individually cultured embryos via Next Generation Sequencing (NGS). MATERIALS AND METHODS: Forty fresh embryos were analyzed. TE and SCM from blastocysts were collected and analyzed. RESULTS: We detected cfDNA in 100% of samples tested. The overall concordance rate between the ni-PGT-A and PGT-A was 27/33 (81.8%). The full concordance rate was 21/33 (63.6%). The aneuploidy agreement was 91.66%, and the euploidy agreement was 76.19%. CONCLUSION: We found a good accordance between TE and SCM analysis, suggesting that niPGT-A could be a reliable alternative for chromosomal abnormalities assessment of in vitro cultured embryos.

Molecular Drivers of Developmental Arrest in the Human Preimplantation Embryo: A Systematic Review and Critical Analysis Leading to Mapping Future Research.

Developmental arrest of the preimplantation embryo is a multifactorial condition, characterized by lack of cellular division for at least 24 hours, hindering the in vitro fertilization cycle outcome. This systematic review aims to present the molecular drivers of developmental arrest, focusing on embryonic and parental factors. A systematic search in PubMed/Medline, Embase and Cochrane-Central-Database was performed in January 2021. A total of 76 studies were included. The identified embryonic factors associated with arrest included gene variations, mitochondrial DNA copy number, methylation patterns, chromosomal abnormalities, metabolic profile and morphological features. Parental factors included, gene variation, protein expression levels and infertility etiology. A valuable conclusion emerging through critical analysis indicated that genetic origins of developmental arrest analyzed from the perspective of parental infertility etiology and the embryo itself, share common ground. This is a unique and long-overdue contribution to literature that for the first time presents an all-inclusive methodological report on the molecular drivers leading to preimplantation embryos' arrested development. The variety and heterogeneity of developmental arrest drivers, along with their inevitable intertwining relationships does not allow for prioritization on the factors playing a more definitive role in arrested development. This systematic review provides the basis for further research in the field.

Erythropoitein Increases In Vitro Motility and Vitality of Human Spermatozoa.

BACKGROUND/AIM: Erythropoietin and its receptor are expressed in the male reproductive system. Initial studies have shown that erythropoietin affects the motility of spermatozoa. The aim of the present study was to investigate the in vitro effect of erythropoietin in the motility and vitality of human spermatozoa. MATERIALS AND METHODS: Forty-three semen samples, obtained after 2-4 days of abstinence from sex, were analyzed and processed using density gradient centrifugation. Aliquots containing one million of spermatozoa were treated with either erythropoietin, at concentrations of 10 and 100 mIU/µl or standard culture medium for one hour. RESULTS: Progressive motility and vitality of spermatozoa significantly increased following treatment with erythropoietin. The effect was not dose-dependent. CONCLUSION: The supplementation of culture medium with erythropoietin improves sperm processing in terms of vitality and motility. Future research should focus on the effects of erythropoietin on sperm capacitation as well as on the signal transduction pathways activated by erythropoietin and its receptor in spermatozoa.

IGF-I and NGFß enhance in vitro progressive motility and vitality of human spermatozoa.

PURPOSE: Progressive motility (PM) and vitality are positively associated with fertilization ability of spermatozoa. Here, the effects of IGF-I and NGFß on PM and vitality of human spermatozoa were investigated. METHODS: Forty-three volunteers gave semen samples after 2-3 days of sexual abstinence. Each sample was processed with density gradient centrifugation and sperm washing. The pellet was divided into 3 aliquots. An aliquot containing one million of progressively motile spermatozoa was incubated for an hour (37°C) in standard culture medium (control group), and two aliquots with the same number of progressively motile spermatozoa were incubated in medium supplemented with IGF-I or NGFß. Two concentrations of IGF-I (100 ng/ml and 1000 ng/ml) and NGFß (0,5 ng/ml and 5 ng/ml) were tested. RESULTS: Both growth factors significantly increased PM and vitality in comparison with control either at the low or the high concentration. IGF-I seemed to be more effective than NGFß. The effects did not seem to be dose dependent with the exception of the effect of IGF-I on vitality. CONCLUSIONS: The enhancement of PM and vitality of human spermatozoa by IGF-I and NGFß opens new ways for the improvement of sperm processing. Further research is needed to determine the most effective concentrations.

Temperature Decline in Embryological Culture Dishes outside Incubator.

BACKGROUND: In embryological culture dishes, there is a temperature decline when they are removed outside incubators. This study aimed at investigating the effects of this temperature decline within a certain time frame, the type of culture dish with or without the use of laminar air flow and whether it is possible to achieve a sufficient thermal control with the use of a heating stage. MATERIALS AND METHODS: In this experimental study, the temperatures of four different types of polystyrene dishes [50 mm intracytoplasmic sperm injection (ICSI), 35 mm, 60 mm, 90 mm], filled with culture medium and oil were recorded for a period of 10 minutes outside the incubator. Temperature was measured with an infrared thermographic camera. The reference temperature was 37°C. Four parameters were analyzed: the type of dishes, air flow, a heating stage at 37°C and 38.5°C. RESULTS: There was a time-dependant significant temperature decline outside the incubator in all types of dishes and under all experimental conditions. Under air flow temperature decline increased compared to the no air flow condition. The use of a heating stage at either 37°C or 38.5°C slightly improved the situation in most cases. After three minutes out of the incubator without a heating stage and air flow, the temperature was <34°C; with air flow and without a heating stage the temperature was <33°C. When a heating stage was used, the temperature was <36°C, except when using ICSI dishes. When ICSI dishes were on a heating stage they maintained a temperature close to 37°C with or without air flow. In all experimental conditions the highest decline was recorded with the 90 mm dishes. CONCLUSION: Time is crucial for managing the temperature decline in culture dishes when out of the incubator. Under air laminar flow, the heat loss is greater, when with a heating stage at 37°C or better at 38.5°C this loss decreases but still exists. ICSI flat bottom dishes give the best results when heated stages are used. Flat bottom dishes maintain the temperature rather efficiently. Based on our findings, the use of flat bottom dishes should become a universal practice in in vitro fertilization (IVF).

Pharmacogenomics in IVF: A New Era in the Concept of Personalized Medicine.

Pharmacogenomics is a promising approach in the field of individualized medicine in in vitro fertilization (IVF) treatment that aims to develop optimized pharmacotherapy depending on the genetic background of each infertile woman, thus to ensure maximum effectiveness of the medication used, with minimal side effects. The unique genetic information of each infertile woman, in combination with already known, as well as new predictors of ovarian response and the progress of pharmacoepigenomics, is anticipated to greatly benefit the process of controlled ovarian stimulation. This review analyses current data on IVF pharmacogenomics, a new approach that is gradually moving to the frontline of modern IVF treatment.

Vitrification of Human Germinal Vesicle Oocytes: before or after In Vitro Maturation?

BACKGROUND: The use of immature oocytes derived from stimulated cycles could be of great importance, particularly for urgent fertility preservation cases. The current study aimed to determine whether in vitro maturation (IVM) was more successful before or after vitrification of these oocytes. MATERIALS AND METHODS: This prospective study was performed in a private in vitro fertilization (IVF) center. We collected 318 germinal vesicle (GV) oocytes from 104 stimulated oocyte donation cycles. Oocytes were divided into two groups according to whether vitrification was applied at the GV stage (group 1) or in vitro matured to the metaphase II (MII) stage and then vitrified (group 2). In the control group (group 3), oocytes were in vitro matured without vitrification. In all three groups, we assessed survival rate after warming, maturation rate, and MII-spindle/chromosome configurations. The chi-square test was used to compare rates between the three groups. Statistical significance was defined at P<0.05 and we used Bonferroni criterion to assess statistical significance regarding the various pairs of groups. The Statistical Package for the Social Sciences version 17.0 was used to perform statistical analysis. RESULTS: There was no significant difference in the survival rate after vitrification and warming of GV (93.5%) and MII oocytes (90.8%). A significantly higher maturation rate occurred when IVM was performed before vitrification (82.9%) compared to after vitrification (51%). There was no significant difference in the incidence of normal spindle/ chromosome configurations among warmed oocytes matured in vitro before (50.0%) or after (41.2%) vitrification. However, a higher incidence of normal spindle/chromosome configurations existed in the in vitro matured oocytes which were not subjected to vitrification (fresh oocytes, 77.9%). CONCLUSION: In stimulated cycles, vitrification of in vitro matured MII oocytes rather than GV oocytes seems to be more efficient. This approach needs to be verified in nonstimulated fertility preservation cases.

Relationship between Chlamydia-Ureaplasma-Mycoplasma Genital Detection with Semen Concentration and Motility among Greek Men.

One hundred and seventy two men at the State of Thessaly, Greece, inquiring semen analysis were enrolled in the study in order to investigate the incidence of Chlamydia, Ureaplasma and Mycoplasma (C-U-M) genera in respect to total sperm number (TSN), progressive motility (grades a and b) and total motility (grades a, b and c). Putative relation of C-U-M acquirement with sexual behavior was also investigated. Incidence of C-U-M among non-oligozoospermic and oligozoospermic men was similar. Νο correlation of C-U-M carriage to either oligozoospermia or asthenozoospermia was found. The tested semen parameters were negatively correlated to the age of sexual intercourse initiation and positively correlated to the number of sex partners. Early age of sexual intercourse initiation or high number of sexual partners was not statistical significantly correlated to C-U-M acquirement. Overall, TSN and motility (either progressive or total) were not influenced by the presence of C-U-M genera in a sample of Greek population undergoing semen evaluation. To distinguish the role of C-U-M in male infertility and clarify the so far controversial scarce literature, large control case studies are needed using nucleic acid amplification techniques to detect these pathogens.

Subcutaneous and total fat at L4-L5 and subcutaneous, visceral and total fat at L3-L4 are important contributors of fasting and postprandial adiponectin levels.

OBJECTIVES: Insulin resistance and central obesity have been implicated in the pathogenesis of hypoadiponectinemia in obesity. The aim of this study is to evaluate circulating post-prandial adiponectin in relation to glucose and insulin metabolism, indexes of insulin resistance and sensitivity and, indexes of body fat accumulation and distribution in obese men. METHODS: Twenty-eight non-diabetic men underwent an OGTT followed by an oral fat load and were studied at baseline and for 5 h post-prandially for serum adiponectin, glucose and insulin. Insulin resistance was estimated by Homeostasis model assessment (HOMA) and insulin sensitivity by Matsuda index. Body fat accumulation and distribution were evaluated by anthropometric indexes and multiple slices MRI of the abdomen and hip. RESULTS: Adiponectin was negatively correlated to insulin levels. Fasting and area under the curve (AUC) adiponectin levels were negatively correlated to HOMA (both p < 0.01) and positively to Matsuda index (both p < 0.05). Negative correlations between fasting adiponectin and total fat (r = -0.408, p < 0.05), AUC adiponectin and subcutaneous, visceral and total fat (r = -0.375, -0.413 and -0.475 respectively, all p < 0.05) at L3-L4 were found, and negative correlations between fasting adiponectin and subcutaneous (r = -0.402, p < 0.05) and total fat (r = -0.491, p < 0.05) and between AUC adiponectin and subcutaneous and total fat (r = -0.506 and -0.547, respectively, both p < 0.01) were present at L4-L5. CONCLUSIONS: Circulating adiponectin is inversely correlated to both visceral and subcutaneous fat in non-diabetic men, implying that both compartments are important for adiponectin levels. The best correlation is found at measurement site L4-L5.

Conventional semen parameters and DNA fragmentation in relation to fertility status in a Greek population.

OBJECTIVES: Our study aimed to investigate the possible correlations between conventional seminal parameters and DNA fragmentation in specific groups of Greek men, selected in relation to their fertility history and to verify the validity of the recent WHO reference values for the basic semen analysis in this population. STUDY DESIGN: A total of 770 subject data were evaluated in three distinct groups: fertile men with children naturally conceived within one year of unprotected intercourse (n=78), subfertile men, having achieved pregnancies either naturally or by Assisted Reproduction Techniques, not resulting in live births (n=153) and infertile men, failing to produce either pregnancies or children (n=539). Semen volume, sperm concentration, total count, rapid and total progressive motility and morphology were evaluated following the World Health Organization (2010) methods. DNA fragmentation was assessed by the Sperm Chromatin Dispersion assay. The 5th percentile, as well as the 95% confidence intervals (CI) for each parameter, were calculated by the method of bootstrapping. Statistical correlations between the examined parameters were sought using the Spearman R test (p<0.05). RESULTS: A significant inverse correlation was established between DNA fragmentation and sperm concentration, total count, progressive motility (rapid and total) and normal morphology in subfertile and infertile men (p<0.05). No statistically significant correlations were remarked between the conventional semen parameters and the levels of DNA fragmentation in our group of fertile men. Concordance was established between the reference limits issued by the WHO 2010 for the basic semen parameters and semen quality of fertile men in the studied population. CONCLUSIONS: The variability of correlations established between DNA fragmentation and the conventional seminal profile in relation to fertility status indicates that they are independent attributes of semen quality, justifying the assessment of both during a comprehensive evaluation of male infertility. Moreover, the WHO 2010 reference limits were found adequately descriptive of seminal normality in Greek men.

Oocyte and embryo vitrification in the IVF laboratory: a comprehensive review.

Vitrification is an excellent tool in the IVF laboratory, enabling options and offering flexibility in assisted reproduction. The technology of cryopreservation has been underway since the early 20th century. The advent of vitrification has advanced the expectations in routine clinical practice in the IVF laboratory presenting impressive results both in post-thaw survival, and in clinical pregnancy rates, as well as significantly enhancing clinical results on preimplantation genetic diagnosis (PGD). Contradicting opinions have been published recently on the limitations and potential that vitrification has in the laboratory, as well as on the optimal approach to employ vitrification in IVF. This review aims to present a comprehensive analysis of the practical aspects of vitrification including concerns and options regarding its use on oocytes and embryos while comparing it with the traditional "slow-freezing" cryopreservation technique.

Human sperm DNA fragmentation and its correlation with conventional semen parameters.

BACKGROUND: The initial step in the diagnostic investigation of male infertility has been traditionally based on the conventional seminal profile. However, there are significant limitations regarding its ability to determine the underlying mechanisms that cause the disorder. Sperm DNA fragmentation has emerged as a potential causative factor of reproductive failure and its assessment has been suggested as a useful adjunct to the laboratory methodology of male infertility evaluation, especially before the application of assisted reproduction technology (ART). METHODS: A review of recent bibliography was carried out in PubMed by the use of relevant keywords, in order to evaluate the possible correlation between the conventional seminal parameters and sperm DNA fragmentation assessment as diagnostic tools in male infertility evaluation. RESULTS: A comprehensive diagnostic approach of male infertility should be based on a combination of diagnostic attributes, derived from the conventional semen analysis, as well as the investigation of genomic integrity testing. CONCLUSION: Due to its strong correlation with several aspects of ART procedures and further consequences for the offspring, sperm DNA fragmentation is a parameter worth integrating in routine clinical practice. However, additional large scale studies focusing on specific subgroups of infertile men who may benefit from an efficient therapeutic management based on the optimization of sperm DNA integrity are needed.

Association between AMH, oocyte number and availability of embryos for cryopreservation in IVF.

AIM: To investigate possible associations between serum anti-Müllerian hormone (AMH) levels, the number of oocytes collected and the availability and suitability of produced embryos for cryopreservation in in-vitro fertilization (IVF) cycles. PATIENTS AND METHODS: Sixty women in their first IVF/intracytoplasmic sperm injection (ICSI) cycle were studied. The short stimulation protocol was used for controlled ovarian hyperstimulation. AMH levels were measured during the menstrual cycle preceding treatment. RESULTS: A strong, positive correlation between AMH and the number of collected oocytes was found. The patients with available and suitable embryos for cryopreservation had significantly higher levels of AMH. CONCLUSION: AMH appears to be a valuable marker mainly for ovarian reserve and response to IVF treatment. AMH levels are strongly associated with the number of retrieved oocytes and the availability of supernumerary embryos suitable for cryopreservation.

Soluble FAS and FAS ligand levels in seminal plasma: association with basic parameters of semen analysis.

BACKGROUND/AIM: Binding of FAS ligand (FASL) to its physiological receptor FAS, induces the activation of caspase-8, which triggers cell death. The FAS-FASL system regulates germ cell death. In this study, the role of the FAS-FASL system in male infertility was examined. PATIENTS AND METHODS: 72 samples were used (age=38.76 ± 9.06 years). Basic semen analysis was performed according to the WHO Laboratory Manual. Soluble (s) forms of FAS and FASL were measured in seminal plasma using commercially available immunoassay kits. RESULTS: Among the examined samples, 24 were normal and 48 abnormal, as evaluated by basic semen analysis. sFAS and sFASL levels in abnormal samples were slightly higher than in the normal ones. In all samples, sFAS correlated negatively with pH. In normal samples, sFAS was positively correlated with sperm concentration. In abnormal samples, sFAS strongly correlated with sFASL. CONCLUSION: Both factors of the FAS system were detected in seminal plasma. Further studies are necessary to shed light into the possible role of FAS-FASL system in male infertility.