Spermatozoa isolation with Felix™ outperforms conventional density gradient centrifugation preparation in selecting cells with low DNA damage

Abstract

BackgroundThe optimization of spermatozoa preparation techniques in order to obtain cell fractions enriched with structurally and functionally “superior” spermatozoa is a key objective of the assisted reproduction industry.ObjectivesThe purpose of this study was to evaluate a recent development of an electrophoretic spermatozoa separation device (Felix™, Memphasys Ltd, Sydney, Australia) and to compare its performance with conventional spermatozoa preparation by density gradient centrifugation (DGC). Particular attention was paid to the evaluation of sperm DNA/nuclear integrity.Materials & methodsA cohort of 29 human semen samples was studied. Semen samples were analyzed fresh and after DGC or Felix™ preparation. Semen parameters monitored included sample volume, sperm count, total motility, progressive motility, sperm DNA fragmentation using the Sperm Chromatin Structure Assay and sperm DNA oxidation.ResultsSpermatozoa preparation with Felix™ resulted in significantly improved spermatozoa fractions with higher progressive motility, lower sperm DNA fragmentation, and lower sperm DNA oxidation compared with raw semen and DGC‐prepared spermatozoa.Discussion & conclusionThe data collected in this study support the preparation of spermatozoa by the Felix™ system as it allows selection of spermatozoa with the highest progressive motility as well as the lowest nuclear/DNA damage. These improved sperm parameters, along with the fact that the Felix™ separation process is very fast and highly standardized, should be of great interest to the assisted reproduction technologies industry.

New horizons in human sperm selection for assisted reproduction

“…However, beyond masking the allogeneic properties of the sperm cell, the accompanying increase in electronegativity brought about by sialyation has formed the basis of electrophoretic separation techniques designed to rapidly fractionate mature spermatozoa away from other deleterious ejaculate contaminates (i.e., immature germ cells, bacteria, and leucocytes) (90) (Figure 1). One such recent development, now marketed under the trademark of the Felix Sperm Separation System, has shown promise for the isolation of suspensions of viable, morphologically normal spermatozoa with high levels of total and progressive motility, and low levels of DNA damage (37,(90)(91)(92)(93). Clinical compatibility has also been demonstrated with biopsied material, snap-frozen sperm suspensions and cryostored semen, and the first report of a human pregnancy and live birth using electrophoretically isolated spermatozoa (91).…”

Sperm DNA integrity: a special issue exploring the causes, consequences, and treatment of DNA damage in human spermatozoa

“…If we cannot yet treat the oxidative stress at source perhaps, in the interim, we can develop methods for the physical selection of spermatozoa exhibiting minimal levels of oxidative stress and DNA damage for use in assisted conception procedures. In this Special Issue, Villeneuve et al 16 . describe a novel electrophoretic sperm isolation procedure that achieves this end.…”

“…If we cannot yet treat the oxidative stress at source perhaps, in the interim, we can develop methods for the physical selection of spermatozoa exhibiting minimal levels of oxidative stress and DNA damage for use in assisted conception procedures. In this Special Issue, Villeneuve et al 16 describe a novel electrophoretic sperm isolation procedure that achieves this end. In comparison with conventional DGC procedures, this device isolated spermatozoa with significantly improved motility, reduced DNA fragmentation, and dramatically lower levels of oxidative DNA damage; moreover, these outcomes were achieved in a fraction of the time (∼6 min) taken by DGC (typically ∼55 min).…”