The Use of Non-Apoptotic Sperm Selected by Magnetic Activated Cell Sorting (MACS) to Enhance Reproductive Outcomes: What the Evidence Says

The paternal clock: Uncovering the consequences of advanced paternal age on sperm DNA fragmentation

The objective of the study was to investigate the relationship between advanced paternal age and sperm DNA fragmentation (SDF) levels, specifically identifying the age at which a significant increase in SDF occurs. This is a retrospective cohort study involving 4250 consecutive semen samples from patients presenting for infertility evaluation. Patients were stratified into seven age groups: < 26 (n = 36; 0.8 %), 26-30 (n = 500; 11.8 %), 31-35 (n = 1269; 29.9 %), 36-40 (n = 1268; 29.8 %), 41-45 (n = 732; 17.2 %), 46-50 (n = 304; 7.2 %), > 50 (n = 141; 3.3 %). The main outcome measures included comparing mean SDF levels throughout different age groups and assessing the prevalence of normal, intermediate, and high SDF among the age groups. A positive correlation was observed between paternal age and SDF (r = 0.17, p < 0.001). SDF remained relatively constant until the age of 35 but increased significantly beyond age 35. Mean SDF levels in the older age groups (36-40, 41-45, 46-50, and >50 years) were significantly higher than in the younger age groups (<26, 26-30, and 31-35 years) (p < 0.001). The prevalence of normal SDF was highest among the younger age groups, whereas the prevalence of high SDF was highest among the older age groups. Interestingly, the prevalence of intermediate SDF was relatively constant throughout the age groups (ranging between 29.8 % to 37.2 %). The increase in SDF after the age of 35 highlights the importance of considering male age in infertility evaluations. Assessing SDF in men over the age of 35 is crucial in couples seeking to conceive.

Emerging trends in sperm selection: enhancing success rates in assisted reproduction

This comprehensive review explores the evolving landscape of sperm selection techniques within the realm of Assisted Reproductive Technology (ART). Our analysis delves into a range of methods from traditional approaches like density gradient centrifugation to advanced techniques such as Magnetic-Activated Cell Sorting (MACS) and Intracytoplasmic Morphologically Selected Sperm Injection (IMSI). We critically assess the efficacy of these methods in terms of sperm motility, morphology, DNA integrity, and other functional attributes, providing a detailed comparison of their clinical outcomes. We highlight the transition from conventional sperm selection methods, which primarily focus on physical characteristics, to more sophisticated techniques that offer a comprehensive evaluation of sperm molecular properties. This shift not only promises enhanced prediction of fertilization success but also has significant implications for improving embryo quality and increasing the chances of live birth. By synthesizing various studies and research papers, we present an in-depth analysis of the predictability of different sperm selection procedures in ART. The review also discusses the clinical applicability of these methods, emphasizing their potential in shaping the future of assisted reproduction. Our findings suggest that the integration of advanced sperm selection strategies in ART could lead to more cost-effective treatments with reduced duration and higher success rates. This review aims to provide clinicians and researchers in reproductive medicine with comprehensive insights into the current state and future prospects of sperm selection technologies in ART.

Enrichment of thawed boar spermatozoa with an intact membrane using Magnetic Activated Cell Sorting

Not all boar sperm samples survive cryopreservation well. A method of eliminating damaged sperm might enable more cryopreserved boar semen to be used for pig breeding. In this study we investigated the use of Magnetic Activated Cell sorting (MACS) to eliminate damaged sperm from thawed boar semen samples. The thawed samples were mixed with Dead cell removal particles and were applied to the column in a SuperMACS II. Different fractions were collected: Original sample (O), Flow-through (FT), and Eluate (E). Sperm membrane integrity, mitochondrial membrane potential and reactive oxygen species were evaluated by flow cytometry after staining with SYBR 14 and propidium iodide, or 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimidazolylcarbocyanine iodide, or hydroethidine and dichlorodihydrofluorescein diacetate, respectively. The FT samples had increased membrane integrity, a greater proportion of sperm with high mitochondrial membrane potential and a greater proportion of sperm negative for hydrogen peroxide than O samples (P<0.0001), which in turn had increased membrane integrity than E samples (P <0.0001). However, differences were seen between boars. The FT samples had increased values of live, superoxide positive sperm than O samples (P <0.0001) and O samples had greater values than E samples (P <0.0001), while there was no effect of boar. Sperm quality was best in the FT fraction, comprising approximately 32% of the sperm sample. In conclusion, although there were differences between boars, MACS separation can improve sperm quality in thawed semen samples. It would be interesting to see if this improvement is reflected in fertility outcomes.

In cases with raised sperm DNA fragmentation, can sperm selection by magnetic-activated cell sorting or testicular sperm aspiration help improve reproductive outcomes?

PURPOSE

To evaluate the efficacy of magnetic-activated cell sorting (MACS) or testicular sperm aspiration (TESA) to improve reproductive outcomes in cases with elevated sperm DNA fragmentation undergoing assisted reproduction.

METHODS

This randomized controlled trial included couples with failed IVF cycles and sperm DNA fragmentation > 30%. Sperm DNA fragmentation was assessed using the sperm chromatin structure assay (SCSA) method. Participants were randomly assigned to either the MACS or TESA group. Testicular sperm retrieval was performed for the TESA group, while MACS involved sperm selection using magnetic beads. Extended blastocyst culture, freeze all policy of blastocysts by vitrification, and frozen embryo transfer were undertaken as per clinic's standard operating protocols. Blastocyst formation rate, implantation rate, miscarriage rate, multiple pregnancy rate, and live birth rate were analyzed and compared between MACS and TESA groups.

RESULTS

There were no significant differences in female age, male age, or sperm DNA fragmentation index (DFI) between the MACS and TESA groups. The blastocyst conversion rate was slightly higher in the TESA group (39%) compared to the MACS group (32%). However, the MACS group had a higher implantation rate (50%) than the TESA group (35%). Miscarriage rates, multiple pregnancy rates, and live birth rates did not show statistically significant differences between the groups. A chi-squared test was conducted to compare categorical variables, and t-tests were done to compare continuous variables.

CONCLUSION

In cases with raised sperm DNA fragmentation, sperm selection by MACS or TESA seems to offer comparable reproductive outcomes. There seems no superiority of one intervention over the other in cases with raised sperm DNA fragmentation undergoing assisted reproduction. Both interventions seem to be beneficial for couples seeking assisted reproduction with raised sperm DNA fragmentation.

An Alternative Application of Magnetic-Activated Cell Sorting: CD45 and CD235a Based Purification of Semen and Testicular Tissue Samples

Magnetic activated cell sorting (MACS) is a well-known sperm selection technique, which is able to remove apoptotic spermatozoa from semen samples using the classic annexinV based method. Leukocytes and erythrocytes in semen samples or in testicular tissue processed for in vitro fertilization (IVF) could exert detrimental effects on sperm. In the current study, we rethought the aforementioned technique and used magnetic microbeads conjugated with anti-CD45/CD235a antibodies to eliminate contaminating leukocytes and erythrocytes from leukocytospermic semen samples and testicular tissue samples gained via testicular sperm extraction (TESE). With this technique, a 15.7- and a 30.8-fold reduction could be achieved in the ratio of leukocytes in semen and in the number of erythrocytes in TESE samples, respectively. Our results show that MACS is a method worth to reconsider, with more potential alternative applications. Investigations to find molecules labeling high-quality sperm population and the development of positive selection procedures based on these might be a direction of future research.