Seminal Plasma Annexin A5 Concentration is not Associated with Male Subfertility and cannot be Influenced by Folic Acid and Zinc Sulfate Treatment

Annexin A5 (anxA5) is abundantly present in seminal plasma, however, its endogenous function in seminal plasma is not known. Recently, we demonstrated that folic acid and zinc sulfate intervention increased sperm count. To explore the involvement of anxA5 in human (sub)fertility, we measured anxA5 concentrations in seminal plasma, using sandwich ELISA, before and after folic acid (5 mg/day) and zinc sulfate (66 mg/day) intervention in 86 fertile and 78 subfertile males participating in a randomized placebo controlled intervention study. Seminal plasma anxA5 concentrations at baseline were not significantly different between fertile and subfertile males, (median) 5.2 μg/mL (25th–75th percentile: 4.2–7.2), and 5.6 μg/mL (4.3–6.7), respectively. The various treatments did not affect seminal plasma anxA5 concentrations. In conclusion, seminal plasma anxA5 concentration is not associated with male factor subfertility and the observed increase in sperm count after folic acid and zinc sulfate treatment cannot be explained by a change in the seminal plasma anxA5 concentration. Further studies are needed to elucidate the mechanisms responsible for the beneficial effect of this intervention treatment on sperm count.