Influence of sperm DNA damage on human preimplantation embryo metabolism.

Understanding the embryo metabolic response to sperm induced specific abnormalities could help in developing the metabolic markers to prevent the transfer of embryos carrying sperm mediated defects. In this study, NMR based metabolic profiling of the embryo spent media was employed in 34 patients undergoing ICSI cycles. Processed ejaculates were tested for DNA damage using comet assay. Relative intensities of the metabolites from 74 embryo spent media samples from 34 patients and 23 medium controls were profiled using 1H NMR and compared between 'male-factor' and control groups. Relative intensities in the subgroups which are independent of patients with male factor or tubal factors, but related to the extent of sperm DNA damage were also compared. Sperm characteristics including DNA damage levels (Olive tail moment, OTM) were significantly different between 'male factor' and control groups (P<0.001-0.0001). Of the metabolites analyzed, glutamine intensity was significantly lower in 'male factor' group (P<0.01) whereas, pyruvate intensity was significantly lower in embryos derived from the processed sperm fraction having <1.0 OTM (P=0.003). In contrast glutamine and alanine intensities were significantly higher in the embryos derived from sperm population having OTM <1.0. (P=0.03 & 0.005 respectively). Pyruvate to alanine ratio was significantly lower in <1.0 OTM group (P<0.0001). This study indicates that increased level of sperm DNA damage in the processed ejaculate affects embryo metabolism which could be related to embryonic genetic integrity.