Sperm selection for ICSI using annexin V

Semen processing using magnetic-activated cell sorting before ICSI is deemed safe for obstetric and perinatal outcomes: a retrospective multicentre study

RESEARCH QUESTION

Is magnetic-activated cell sorting (MACS) a safe semen sample processing technique for newborns and mothers when used for semen processing prior to intracytoplasmic sperm injection (ICSI) cycles?

DESIGN

This retrospective multicentre cohort study involved patients undergoing ICSI cycles with either donor or autologous oocytes from January 2008 to February 2020. They were divided into two groups: those who underwent standard semen preparation (reference group) and those who had an added MACS procedure (MACS group). A total of 25,356 deliveries were assessed in the case of cycles using donor oocytes, and 19,703 deliveries from cycles using autologous oocytes. Of these, 20,439 and 15,917, respectively, were singleton deliveries. Obstetric and perinatal outcomes were retrospectively assessed. All means, rates and incidences were computed per live newborn in each study group.

RESULTS

There were no significant differences between the main obstetric and perinatal morbidities affecting the mothers' and newborns' well-being between groups using either donated or autologous oocytes. There was a significant increase in the incidence of gestational anaemia in both subpopulations (donor oocytes P = 0.01; autologous oocytes P < 0.001). However, this incidence was within the estimated prevalence for gestational anaemia in the general population. There was a statistically significant decrease in preterm (P = 0.02) and very preterm (P = 0.01) birth rates in the MACS group in cycles using donor oocytes.

CONCLUSIONS

The use of MACS during semen preparation before ICSI using either donor or autologous oocytes appears to be safe for the mothers' and newborns' well-being during pregnancy and birth. Nevertheless, a close follow-up of these parameters in the future is advised, especially concerning anaemia, in order to detect even smaller effect sizes.

Selecting motile, non-apoptotic and induced spermatozoa for capacitation without centrifuging by MACS-Up method

In newly improved MACS-Up method, magnetic field has been applied to separate non-apoptotic spermatozoa directly from the neat semen. The spermatozoa during passing through a viscous layer, located on the neat semen, contacted with progesterone and induced for the capacitation. Then, a clean population of non-apoptotic, and capacitated spermatozoa were selected in the pure culture media. Selected spermatozoa may be useful for use in ART. The 80 semen samples from normozoospermic individuals were divided separately into 4 attempts. Semen analysis, SCSA (sperm chromatin structure assay), FLICA (fluorescein-labelled inhibitors of caspase) methods, immunoassay of phosphorylation of tyrosine residues of sperm proteins, nuclear DNA integrity, caspase 3 activity and sperm capacitation rate were all performed for evaluation of sperm parameters respectively. To examine all aspects, the MACS-Up method compared with DGC (density gradient centrifuging) and MACS-DGC methods separately. This method can isolate non-apoptotic spermatozoa directly from the neat semen, which has similar performance compared to the MACS-DGC method. Movement and passing spermatozoa through the viscous layer, and contact with progesterone, significantly induced spermatozoa for capacitation compared with the control group. Also, the MACS-Up in comparison with routine DGC method could select spermatozoa with significantly higher total and progressive motility, DNA integrity, induced sperm population for capacitation and normal morphology. MACS-Up can be developed as an effective, short-time, and ease of performing method and used practically to select functional spermatozoa as novel sperm selection procedure. However, for clinical use of MACS-Up, all clinical aspects of this method should be considered and evaluated.

Simulating nature in sperm selection for assisted reproduction

Sperm selection in the female reproductive tract (FRT) is sophisticated. Only about 1,000 sperm out of millions in an ejaculate reach the fallopian tube and thus have a chance of fertilizing an oocyte. In assisted reproduction techniques, sperm are usually selected using their density or motility, characteristics that do not reflect their fertilization competence and, therefore, might result in failure to fertilize the oocyte. Although sperm processing in in vitro fertilization (IVF) and intrauterine insemination (IUI) bypasses many of the selection processes in the FRT, selection by the cumulus mass and the zona pellucida remain intact. By contrast, the direct injection of a sperm into an oocyte in intracytoplasmic sperm injection (ICSI) bypasses all natural selection barriers and, therefore, increases the risk of transferring paternal defects such as fragmented DNA and genomic abnormalities in sperm to the resulting child. Research into surrogate markers of fertilization potential and into simulating the natural sperm selection processes has progressed. However, methods of sperm isolation - such as hyaluronic acid-based selection and microfluidic isolation based on sperm tactic responses - use only one or two parameters and are not comparable with the multistep sperm selection processes naturally occurring within the FRT. Fertilization-competent sperm require a panel of molecules, including zona pellucida-binding proteins and ion channel proteins, that enable them to progress through the FRT to achieve fertilization. The optimal artificial sperm selection method will, therefore, probably need to use a multiparameter tool that incorporates the molecular signature of sperm with high fertilization potential, and their responses to external cues, within a microfluidic system that can replicate the physiological processes of the FRT in vitro.

Oxidative stress and male infertility

BACKGROUND

Between 30% and 80% of patients with male infertility produce excessive reactive oxygen species (ROS) in their ejaculate even though the cause of male infertility is unexplained in approximately half of cases. The strong connection between oxidative stress (OS) and male infertility has led recent investigators to propose the term "Male Oxidative Stress Infertility (MOSI)" to describe OS-associated male infertility.

METHODS

We searched the PubMed database for original and review articles to survey the effects of OS on male infertility, and then verified the effects and treatments.

MAIN FINDINGS

Seminal plasma contains many antioxidants that protect sperm from ROS, because low amounts of ROS are required in the physiological fertilization process. The production of excessive ROS causes OS which can lower fertility through lipid peroxidation, sperm DNA damage, and apoptosis. Several assays are available for evaluating OS, including the MiOXSYS® analyzer to measure oxidation-reduction potential. Several measures should be considered for minimizing OS and improving clinical outcomes.

CONCLUSION

Accurately diagnosing patients with MOSI and identifying highly sensitive biomarkers through proteomics technology is vital for better clinical outcomes.

Magnetic-Activated Cell Sorting (MACS): A Useful Sperm-Selection Technique in Cases of High Levels of Sperm DNA Fragmentation

Magnetic-activated cell sorting (MACS) can be used to separate apoptotic sperm with high proportions of fragmented DNA from the rest, thus improving the overall quality of the seminal sample. Therefore, the aim of this retrospective study was to investigate the efficiency of the MACS technique to increase reproductive outcomes in patients with high levels of sperm DNA fragmentation (SDF) undergoing intracytoplasmic sperm-injection (ICSI) cycles. In this study, we analyzed a total of 724 assisted-reproduction-technique (ART) cycles that were divided into two groups: the study group (n = 366) in which the MACS selection technique was performed after density-gradient centrifugation (DGC), and the control group (n = 358) in which only DGC was used for sperm selection. Reproductive outcomes were analyzed in both groups according to three different ART procedures: preimplantation genetic testing for aneuploidy (PGT-A), and autologous and oocyte-donation cycles. The MACS group showed significantly lower miscarriage rates in autologous ICSI cycles, higher pregnancy rates in oocyte-donation cycles, and a significant increase in live-birth rates in both autologous and oocyte-donation cycles. Overall, these results suggested that the MACS technique can be effectively used to eliminate sperm with high SDF levels, and therefore may help to improve reproductive outcomes in couples undergoing ART.

A methodological validation of an easy one-step swimout semen preparation procedure for selecting DNA fragmentation-free spermatozoa for ICSI

The main purpose of this methodological paper was to describe a recently designed one-step ICSI semen preparation swim-out method (called swim-ICSI) and to compare its efficacy with our conventional two-step swim-out method for the selection of motile spermatozoa for ICSI with minimal DNA damage. In this observational cohort study, 42 fresh ejaculate sperm samples for ICSI were included to compare the new swim-ICSI with the conventional swim-out. In a sub-analysis (n = 20), both in-house designed ICSI preparation methods were compared with a commercial magnetic-activated cell sorting test (MACS^® ). Sperm DNA fragmentation (SDF), using Halosperm^® , was determined at different time points during sperm preparation: on the native sample (a), after density gradient centrifugation (DG) (b), on the motile (A + B) spermatozoa selected with conventional swim-out post-DG (c) and selected with swim-ICSI method post-DG (d). For a subgroup (n = 20), SDF was also calculated after MACS (e). The mean SDF significantly reduced after EACH preparation step and reduced to almost zero in the recovered A + B spermatozoa when the semen prepared with DG was further processed for ICSI (swim-ICSI vs. swim-out, p = .001). In conclusion, the optimised one-step and fine-tuned swim-ICSI technique shows the possibility to select a population of spermatozoa with almost zero SDF to be used in ICSI treatments.

Porcine oviductal extracellular vesicles interact with gametes and regulate sperm motility and survival

Once in the female reproductive tract, spermatozoa undergo several modifications to acquire their complete fertilizing ability. Interactions between the oviductal fluid (OF) and gametes contribute to a successful fertilization. Recently, oviductal extracellular vesicles have been identified as an important part of the OF but their interactions with gametes are not fully understood. In the present study, we aim at determining the patterns of interactions between porcine oviductal extracellular vesicles (poEVs) and gametes (spermatozoa and oocytes). Moreover, we evaluate the effect of poEVs on sperm survival and motility to better understand the mechanisms by which poEVs modulate the processes leading to fertilization. Evaluation of poEVs uptake by spermatozoa showed that poEVs bind to spermatozoa in a time and dose dependent manner. Co-incubation of spermatozoa with poEVs (0.2 μg/μL) increased fresh and frozen sperm survival after 6 and 17 h, respectively. By contrast, poEVs supplementation reduced the total and progressive sperm motility after 2 h. Additionally, we demonstrated that poEVs interacted with the cumulus cells, zona pellucida (ZP) and oocyte, being able to cross the ZP. Besides, we showed that poEVs delivered their cargo into the oocyte, by the transfer of OVGP1 protein. In conclusion, our results demonstrated that poEVs are able to interact with both gametes. Besides, the findings from the present study showed that poEVs may participate in maintaining sperm viability and reducing motility, functions associated with the oviduct sperm reservoir. Although further investigations are needed, our results indicate that poEVs can be a potential tool to improve sperm life span during sperm handling and enhance IVF outcomes.

Fibronectin as a new biomarker for human sperm selection in assisted reproductive technology

OBJECTIVE

Fibronectin (FN) is a multifunctional diametric glycoprotein on the surface of the sperm that plays an important role in the sperm-oocyte interaction and fertilization process. The aim of the present study was to assess the FN levels as a sperm surface biomarker for sperm selection in assisted reproductive technology.

MATERIAL AND METHODS

Polyclonal antibody against human FN was produced in rabbit. Its quality, purity, and immune reactivity were assessed by SDS-PAGE and western blot. In addition, the presence of FN on the sperm surface was assessed through immunocytochemistry and flow cytometry. The amount of FN and the sperm quality were assessed in normozoospermia (N) (42 men) and asthenoteratozoospermia (AT) (72 men) groups through sperm chromatin dispersion (SCD), sperm chromatin structure assay (SCSA), and chromatin maturation index (CMI).

RESULTS

The results showed the distribution of FN protein on the equatorial region of the human sperm surface. In addition, the FN levels were found to have a significant difference between the two groups with 24.64±9.08% in N and 16.90±7.27% in AT (p≤0.0001). In addition, FN level negatively correlated with SCD (p≤0.0001), SCSA (p≤0.0001), and CMI (p≤0.001). Threshold values of FN level and DNA fragmentation index (DFI) percentage were 16 and 30 and were identified as cut-off values to determine the N group with a specificity of 83.3% and 81.0% and a sensitivity of 16.8% and 19.0%, respectively. The specificity and sensitivity of FN-DFI were 91.2% and 8.8%, respectively.

CONCLUSION

It appears that FN can be used for the selection of sperm with suitable quality, although future studies are recommended.

Magnetic-activated cell sorting of non-apoptotic spermatozoa improves the quality of embryos according to female age: a prospective sibling oocyte study

PURPOSE

The main aim of our study was to evaluate the benefit of the use of non-apoptotic spermatozoa selected by magnetic-activated cell sorting (MACS) for ICSI procedures for couples in which the women had good prognoses and the male factor of infertility was teratozoospermia.

METHODS

Twenty-six couples were treated with ICSI after MACS selection of non-apoptotic spermatozoa following a sibling oocyte approach. Half of the oocytes were microinjected with conventionally prepared spermatozoa, and the other half were microinjected with non-apoptotic, MACS-selected spermatozoa. To assess the influence of MACS selection of spermatozoa on the outcomes of the ICSI cycles, the fertilization, embryo quality, pregnancy, and delivery rates were evaluated and compared between the sibling oocyte groups.

RESULTS

When subpopulations of couples according to female age were analyzed, a significant difference in quality of blastocyst was observed. More precisely, in a group that was treated with MACS-ICSI, a higher percentage of good quality blastocysts was found among women older than 30 years (75.0 vs. 33.3%; P = 0.028), while there was no difference among younger women. If all included couples were compared regardless of age, no significant difference was observed in the outcome of the ICSI/MACS-ICSI cycles in terms of oocytes and embryos. Additionally, after the ICSI and MACS-ICSI procedures, the morphologies of the prepared spermatozoa were compared. Results showed that the overall percentage of morphologically normal spermatozoa did not differ significantly between the ICSI and MACS-ICSI procedures. However, detailed analyses of the morphologically abnormal spermatozoa revealed significantly more spermatozoa with abnormal tails after MACS-ICSI procedure, which may be potential consequence of the selection procedure. Moreover, the trends towards less spermatozoa with abnormal heads and towards more spermatozoa with abnormal necks and midpieces after MACS-ICSI procedure were revealed, although the differences were not significant.

CONCLUSIONS

Couples dealing with male infertility due to teratozoospermia can benefit from MACS selection of spermatozoa with higher percentage of good quality blastocysts but only when the woman is older than 30 years.

Strategies to improve fertilisation rates with assisted conception: a systematic review

Successful fertilisation is one of the key steps determining success of assisted conception. Various factors including sperm or oocyte pathology and environmental factors have a significant impact on fertilisation rates. This systematic review is aimed to evaluate the existing evidence about factors affecting fertilisation and strategies to improve fertilisation rates. A literature search was performed using Ovid MEDLINE ® (Jan 1950-April 2016), EMBASE (Jan 1950-April 2016), Ovid OLDMEDLINE ®, Pre-MEDLINE (Jan 1950-April 2016) and the Cochrane Library. Relevant key words were used to combine sets of results and a total 243 papers were screened. Only qualitative analysis was performed, as there was major heterogeneity in study design and methodology for quantitative synthesis. Factors affecting fertilisation were divided into sperm- and oocyte-related factors. The methods to improve fertilisation rates were grouped together based on the approach used to improve fertilisation rates. Optimising laboratory condition and procedural effects in techniques is associated with improved fertilisation rates. Various techniques are described to improve fertilisation rates including assisted oocyte activation, physiological intracytoplasmic sperm injection (PICSI) and intracytoplasmic morphologically selected sperm injection (IMSI). This review highlights the promising strategies under research to enhance fertilisation rates. Adequately powered multicentre randomised trials are required to evaluate these techniques before considering clinical application.

Efficient isolation of sperm with high DNA integrity and stable chromatin packaging by a combination of density-gradient centrifugation and magnetic-activated cell sorting

OBJECTIVE

This study was carried out to investigate the correlations of the sperm DNA fragmentation index (DFI) with semen parameters and apoptosis, and to investigate the effects of density-gradient centrifugation (DGC) and magnetic-activated cell sorting (MACS) on reducing the proportion of sperm with DNA fragmentation and protamine deficiency.

METHODS

Semen analysis and a sperm DNA fragmentation assay were performed to assess the correlations between semen parameters and the DFI in 458 semen samples. Sperm with progressive motility or non-apoptosis were isolated by DGC or MACS, respectively, in 29 normozoospermic semen samples. The effects of DGC or MACS alone and of DGC and MACS combined on reducing the amount of sperm in the sample with DNA fragmentation and protamine deficiency were investigated.

RESULTS

The sperm DFI showed a significant correlation (r=-0.347, p<0.001) with sperm motility and morphology (r=-0.114, p<0.05) but not with other semen parameters. The DFI (11.5%±2.0%) of semen samples was significantly reduced by DGC (8.1%±4.1%) or MACS alone (7.4%±3.9%) (p<0.05). The DFI was significantly further reduced by a combination of DGC and MACS (4.1%±1.3%, p<0.05). Moreover, the combination of DGC and MACS (1.6%±1.1%, p<0.05) significantly reduced the protamine deficiency rate of semen samples compared to DGC (4.4%±3.2%) or MACS alone (3.4%±2.2%).

CONCLUSION

The combination of DGC and MACS may be an effective method to isolate high-quality sperm with progressive motility, non-apoptosis, high DNA integrity, and low protamine deficiency in clinical use.

Improving ICSI: A review from the spermatozoon perspective

Intracytoplasmic sperm injection (ICSI) is the most frequently applied method for fertilization making the process of identifying the perfect spermatozoon fundamental. Herein we offer a critical and thorough presentation on the techniques reported regarding (i) handling and preparing semen samples, (ii) identifying and 'fishing' spermatozoa, and (iii) improving key factors, such as motility for a successful ICSI practice. These approaches are suggested to make the process easier and more effective especially in atypical and challenging circumstances. Furthermore, we present an epigrammatic opinion-where appropriate-based upon our collective experience. Techniques such as intracytoplasmic morphologically selected sperm injection, hyaluronic binding, polarized light microscopy, and annexin V agent identification for comparing sperm cells and their chromatin integrity are analyzed. Moreover, for the demanding cases of total sperm immotility the use of the hypoosmotic swelling test, methylxanthines, as well as the option of laser assisted immotile sperm selection are discussed. Finally, we refer to the employment of myoinositol as a way to bioreactively improve ICSI outcome for oligoasthenoteratozoospermic men. The diversity and the constant development of novel promising techniques to improve ICSI from the spermatozoon perspective, is certainly worth pursuing. The majority of the techniques discussed are still a long way from being established in routine practices of the standard IVF laboratory. In most cases an experienced embryologist could yield the same results. Although some of the techniques show great benefits, there is a need for large scale multicenter randomized control studies to be conducted in order to specify their importance before suggesting horizontal application. Taking into consideration the a priori invasive nature of ICSI, when clinical application becomes a possibility we need to proceed with caution and ensure that in the pursuit for innovation we are not sacrificing safety and the balance of the physiological and biological pathways of the spermatozoon's dynamic.

ABBREVIATIONS

ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; PGD: reimplantation genetic diagnosis; IVM: in vitro maturation; HCV/HIV: hepatitis C virus/human immunodeficiency virus; IMSI: intracytoplasmic morphologically selected sperm injection; DGC: density gradient centrifugations; S-U: swim-up; ART: assisted reproduction technology; IUI: intrauterine insemination; PVP: polyvinylpyrrolidone; HA: hyaluronic acid; MSOME: motile sperm organelle morphology examination; ZP: zona pellucida; MACS: magnetic activation cell sorting; HOST: hypo-osmotic swelling test; TESE: testicular sperm extraction; MMP: mitochondrial membrane potential; OAT: oligoasthenoteratozoospermic.

DNA fragmentation in human sperm after magnetic-activated cell sorting

PURPOSE

As fertilization with unselected apoptotic spermatozoa may contribute to failures in assisted reproductive techniques, it has become essential to remove this type of sperm in order to increase the success rates. Magnetic-activated cell sorting (MACS) is a sperm preparation technique that isolates non-apoptotic spermatozoa based on the expression of phosphatidylserine in the membrane of apoptotic sperm. Therefore, we aimed to evaluate whether there was a significant decrease in sperm DNA fragmentation (sDNAfrag) and verify which protocol was the most efficient.

METHODS

Hundred semen samples were allocated into five distinct groups and processed according to a combination of MACS with density gradient centrifugation (DGC) and swim-up (SU) techniques. Sperm DNA fragmentation was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay.

RESULTS

Groups DGC-SU (73.4 %), DGC-MACS-SU (78.9 %), DGC-SU-MACS (53.8 %) and MACS-SU (73.5 %) presented a significant decrease in sDNAfrag but the highest reduction rate was obtained with MACS-DGC-SU (83.3 %). The later was also negatively correlated with sperm vitality, membrane integrity and progressive motility. Additionally, teratozoospermic patients presented a tendency to have lower sDNAfrag reduction rates than asthenozoospermic and asthenoteratozoospermic patients.

CONCLUSIONS

Based on the results, MACS showed potential to optimize the sDNAfrag reduction rate, when applied to raw semen, before DGC and SU, especially in samples with low values of progressive motility, vitality and hypoosmotic swelling test.

Sperm preparation before freezing improves sperm motility and reduces apoptosis in post-freezing-thawing sperm compared with post-thawing sperm preparation

PURPOSE

To evaluate whether sperm preparation (swim-up technique) before freezing improves the percentages of sperm motility, sperm viability, and non-apoptotic spermatozoa after freezing-thawing process compared with preparation after cryopreservation.

METHODS

Semen samples from 65 infertile males were equally divided into two aliquots one of which was processed for swim-up prior to cryopreservation and one of which was processed following cryopreservation. Sperm count, motility, and apoptosis index were measured in each group.

RESULT (S)

The total sperm count and the total motile sperm count decreased after thawing in both the pre-preparation and non-preparation groups compared with neat semen group (P < 0.001). Moreover, the percentage of apoptotic sperm in the pre-preparation group after cryopreservation was lower than that in the non-preparation group (P < 0.05), whereas the percentage of vital sperm with progressive motility was higher than that in the pre-preparation group (P < 0.001).

CONCLUSION (S)

Semen preparation by swim-up before freezing resulted in better sperm quality and fewer apoptotic sperm than sperm preparation after thawing. Therefore, sperm preparation before cryopreservation should be considered in routine sperm cryopreservation.

Magnetic activated cell sorting: an effective method for reduction of sperm DNA fragmentation in varicocele men prior to assisted reproductive techniques

Semen parameters of varicocele men have been usually suspected to exhibit higher levels of abnormalities including DNA fragmentation, reactive oxygen species (ROS) and apoptotic markers. Negative correlation between increased level of DNA fragmentation and assisted reproductive techniques (ART) outcome has been studied by several authors. In the current study, we aim to evaluate the possible value of magnetic activated cell sorting (MACs) technology in reduction of DNA fragmentation in infertile varicocele patients prior to ART. Semen samples, collected from 36 varicocele patients, were prepared by density gradient centrifugation (DGC). Every sample was subsequently divided into two aliquots. One aliquot was kept untouched as pre-MACs control while the other aliquot was subjected to MACs technique, for depletion of apoptotic spermatozoa, and serves as post-MACs test. Sperm count, motility and DNA fragmentations were evaluated for both control and test samples. Post-MACs samples showed no deleterious reduction in total sperm motility (80.64 ± 6.97%) compared with control samples (80.97 ± 7.74%) while sperm DNA fragmentations were significantly reduced in post-MACs samples (9.61 ± 5.62%) compared with pre-MACs controls (12.43 ± 6.29%) (P < 0.05). It can be concluded that MACs technique is a simple, noninvasive, technique that can efficiently reduce DNA fragmentation in infertile varicocele patients prior to ART.

Morphological evaluation of sperm from infertile men selected by magnetic activated cell sorting (MACS)

Electron microscopy analysis performed in five infertile human subjects after sperm selection by swim-up followed by magnetic activated cell sorting (MACS) demonstrated a decrease in the number of spermatozoa with characteristics compatible with cell death. However, no significant differences were found when the swim-up/MACS semen fraction was compared with swim-up fraction alone.

Basic diagnostics in andrology

Basic andrological diagnosis consists of taking the patient's medical history and the couple's history as well as performing a physical examination including genital ultrasound, spermiogram, and hormonal analysis. If needed, a testicular biopsy and genetic testing may also be performed. Recent studies have shown the effect of lifestyle factors on male fertility. Thus, the patient history and clinical/andrological examinations have been broadened to include information on metabolic disorders like obesity and diabetes mellitus. The biggest changes occurred with the publication of the fifth edition of the WHO laboratory manual in 2010 and the introduction of a section on semen analysis in the German Medical Association guidelines (RiliBÄK). The reference values for almost all spermiogram parameters were adapted in an evidence-based approach using worldwide prospective population studies. For central parameters such as sperm motility and morphology, the assessment criteria were changed. New independent markers such as sperm DNA fragmentation rate are now routinely used in clinical diagnosis. For German andrological laboratories, there are now mandatory quality assurance measures for semen analysis (in the German "Rili-BÄK" guidelines). These include duplicate testing of all standard semen parameters and inter-laboratory comparison at regular intervals.

The use of complimentary assays to evaluate the enrichment of human sperm quality in asthenoteratozoospermic and teratozoospermic samples processed with Annexin-V magnetic activated cell sorting

Sperm chromatin integrity may affect the outcomes of assisted reproductive technology (ART). Developing a clinically reliable strategy to enrich sperm samples with high chromatin quality spermatozoa prior to sperm banking or use in ART would thus be advantageous. The objectives of this study were to: (i) assess the sperm chromatin quality in men with different categories of semen parameters; and (ii) evaluate the extents of Annexin-V magnetic-activated cell sorting (MACS) technology coupled with differential density gradient centrifugation (DGC) in improving sperm chromatin quality. Three categories of men from couples attending a university-based fertility clinic were recruited based on their semen parameters: normozoospermic (n = 13), asthenoteratozoospermic (n = 17) and teratozoospermic (n = 12). For each patient, spermatozoa in semen samples were processed first by DGC to enrich the motility and further by MACS to remove spermatozoa showing apoptotic features. The yield and enrichment of sperm quality was evaluated at each step with conventional semen parameters in conjunction with a combination of five complementary assays, to assess sperm maturity, chromatin structure, compaction and DNA integrity (Hyaluronic Binding Assay, SCSA, chromomycine A3 staining and TUNEL and COMET assays). Our results demonstrated that, compared with normozoospermic samples, raw asthenoteratozoospermic and teratozoospermic samples had a higher proportion of spermatozoa containing DNA breaks, but only asthenoteratozoospermic exhibited altered chromatin structure and decreased binding to hyaluronic acid. Interestingly, the DGC appeared to select for more mature spermatozoa with high DNA compaction. More importantly, in all categories of semen samples, Annexin-V MACS allows enrichment of spermatozoa with good chromatin quality as measured by the TUNEL and SCSA. Because effective treatment modalities to improve sperm DNA damage are limited, our results suggest a potential clinical value of MACS as a mean to enhance sperm quality that may improve assisted reproductive outcomes.