Sperm content of postacrosomal WW binding protein is related to fertilization outcomes in patients undergoing assisted reproductive technology

Abstract

Objective: To determine the levels of postacrosomal WW binding protein (PAWP) in the spermatozoa of men that were used clinically for intracytoplasmic sperm injection (ICSI) and to correlate them with infertility treatment outcomes.

Design: Prospective clinical and laboratory study.

Setting: University-based laboratory and infertility clinic.

Patient(s): Men undergoing ICSI for the treatment of couples' infertility (n=110).

Intervention(s): Quantitative analysis of sperm PAWP levels by flow cytometry and developmental analysis of PAWP expression by immunoblotting, immunofluorescence, and immunohistochemistry.

Main outcome measure(s): PAWP flow-cytometric levels and immunolocalization in spermatozoa.

Result(s): A strong positive correlation was found between PAWP expression levels and fertilization rates after ICSI, with high levels of PAWP being associated with higher fertilization rates; the positive correlation was independent of age, DNA fragmentation index, and other sperm parameters. PAWP expression levels were correlated with embryonic development, with high levels of PAWP being associated with a lower number of arrested embryos within 3-5 days post-ICSI. PAWP expression was detected during the late stages of human spermiogenesis in elongating spermatids, confirming previous findings in various animal models.

Conclusion(s): Our clinical data from infertile couples demonstrate significant correlations between sperm PAWP levels and both fertilization rates and normal embryonic development after ICSI. Considering its proposed role in the initiation of oocyte activation, we suggest that PAWP could have potential applications in the diagnosis and treatment of infertility.

Keywords: Fertilization; assisted reproductive technology (ART); intracytoplasmic sperm injection (ICSI); male infertility; perinuclear theca; postacrosomal WW binding protein (PAWP); sperm; spermiogenesis.