Toward the identification of a subset of unexplained infertility: a sperm proteomic approach

Objective: To investigate the male gamete proteome and its relation to blastocyst development and reproductive success. Design: Experimental study. Setting: Research laboratory. Patient(s): Male infertility patients (n = 12) with no known male factor infertility, donated motile sperm after intracytoplasmic sperm injection during an oocyte donor in vitro fertilization cycle. Intervention(s): None. Main Outcome Measure(s): Proteomic profiles of sperm from normozoospermic males. Result(s): Patients were grouped based on day-5 embryo development: group A good blastocyst development (> 35% >= grade 3 BB) and group B poor blastocyst development (< 15% >= grade 3 BB). No differences between the groups were observed for sperm concentration, motility, or Kruger morphology. The in vitro fertilization outcome was statistically significantly different with higher viable implantation rates observed for group A (A = 80% vs. B = 48%). Proteomic analysis of the motile sperm samples revealed 49 proteins with statistically significantly differential abundance in relation to blastocyst development (> 1.5-fold). Twenty-nine proteins showed decreased abundance for group B, including several proteins involved in spermatogenesis, and 20 proteins showed increased abundance for group B, including several heat shock proteins. Conclusion(s): An altered sperm proteome was observed with respect to poor blastocyst development and in vitro fertilization outcome in donor oocyte cycles despite normal sperm testing parameters. These data could represent a novel subset of male factor infertility. Ongoing investigation into the male factor contribution to idiopathic infertility may result in improved patient care and enhanced outcomes. (C) 2014 by American Society for Reproductive Medicine.