Details

Autor(en) / Beteiligte

• Michaelis, Marten
• Gralla, Oliver
• Behrends, Thomas
• Scharpf, Marcus
• Endermann, Tobias
• Rijntjes, Eddy
• Pietschmann, Nicole
• Hollenbach, Birgit
• Schomburg, Lutz

Titel

Selenoprotein P in seminal fluid is a novel biomarker of sperm quality

Ist Teil von

• Biochemical and biophysical research communications, 2014-01, Vol.443 (3), p.905-910

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2014

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• •The serum transporter SePP supplies selenium (Se) to testes for GPX4 biosynthesis.•Testes and GPX4 are preferentially supplied making them selenium-independent.•We find SePP in seminal plasma as a stable biomarker correlating to sperm vitality.•Seminal SePP does not originate in testes but in Se-responsive accessory sex glands.•Besides transport, SePP likely protects sperm as a powerful antioxidative enzyme. Hepatically-derived selenoprotein P (SePP) transports selenium (Se) via blood to other tissues including the testes. Male Sepp-knockout mice are infertile. SePP-mediated Se transport to Sertoli cells is needed for supporting biosynthesis of the selenoenzyme glutathione peroxidase-4 (GPX4) in spermatozoa. GPX4 becomes a structural component of sperm midpiece during sperm maturation, and its expression correlates to semen quality. We tested whether SePP is also present in seminal plasma, potentially correlating to fertility parameters. Semen quality was assessed by sperm density, morphology and motility. SePP was measured by an immunoluminometric assay, and trace elements were determined by X-ray fluorescence spectroscopy. SePP levels were considerably lower in seminal plasma as compared to serum (0.4±0.1mg/l vs. 3.5±1.0mg/l); Se concentrations showed a similar but less pronounced difference (48.9±20.7μg/l vs. 106.7±17.3μg/l). Se and Zn correlated positively in seminal fluid but not in serum. Seminal plasma SePP concentrations were independent of serum SePP concentrations, but correlated positively to sperm density and fraction of vital sperm. SePP concentrations in seminal plasma of vasectomized men were similar to controls indicating that accessory sex glands are a testes-independent source of SePP. This notion was corroborated by histochemical analyses localizing SePP in epithelial cells of seminal vesicles. We conclude that SePP is not only involved in Se transport to testes supporting GPX4 biosynthesis but it also becomes secreted into seminal plasma, likely important to protect sperm during storage, genital tract passage and final journey.