Annexin V magnetic-activated cell sorting versus swim-up for the selection of human sperm in ART: is the new approach better then the traditional one?

Purpose: To investigate whether the sperm fertilizing potential can be improved by selecting a non-apoptotic fraction using magnetic activated cell sorting (MACS), and to compare the results with the conventional swim-up method.

Methods: Twenty five male patients attending the andrology laboratory for sperm DNA fragmentation analysis. The sperm were prepared by density gradient centrifugation (DGC) and subsequently divided into three aliquots. The first was further separated into Annexin V-negative (non-apoptotic) fraction using MACS, the second was further processed by swim-up, while the third was left unseparated as a control. The impact of the combination of DGC with the two sperm preparation techniques on sperm quality was evaluated by comparing 'rapid progressive' motility, normal morphology according to Tygerberg's strict criteria and DNA integrity (by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling [TUNEL]) for each aliquot.

Results: Sperm preparation that combines DGC with conventional swim-up method can provide sperm of higher quality in terms of motility, morphology and extent of DNA fragmentation compared to the Annexin V-negative (non-apoptotic) fraction derived from the combination of DGC with MACS.

Conclusions: Integrating MACS as a part of sperm preparation technique will not improve sperm fertilizing potential to the same extent as the traditional swim-up separation procedure.