Preliminary MALDI-TOF-MS analysis of seminal plasma N-glycome of infertile men.

Glycosylation pattern within reproductive tract is now suggested to be involved in providing female immune tolerance for allograft sperm and developing embryo, but the information whether impaired glycosylation may influence male fertility potential is still limited. We have analyzed seminal plasma N-glycome in pooled samples derived from fertile and infertile men by means of MALDI-TOF/TOF tandem mass spectrometry. Among infertile subjects, normozoospermic, oligozoospermic, asthenozoospermic and oligoasthenozoospermic samples were obtained. Eighty-six oligosaccharides were identified in all the analyzed samples. Differences in the content of unique glycans: high mannose and hybrid type, lacking terminal sialic acid and highly fucosylated were found when samples derived from infertile subjects with different semen patterns were compared to the fertile control. The content of highly branched glycans was 3-fold elevated in normozoospermic infertile men, while the expression of highly fucosylated oligosaccharides was increased in asthenozoospermic, oligozoospermic and oligoasthenozoospermic samples. Sialylation of oligosaccharides was decreased in oligozoospermic, oligoasthenozoospermic and especially asthenozoospermic samples, but increased in infertile normozoospermic subjects. Altered glycosylation observed in seminal plasma may reflect similar changes in sperm surface glycoproteins, and may disturb sperm interaction with female immune system. We suggest that at least some cases of unexplained male infertility may be associated with impaired glycosylation.