Abstract
Study question
The detection of metals in semen offers a new field in the study of male infertility.
Summary answer
Normozoospermia is associated with higher amounts of Fe. In males with pathological spermiogram, the percentage of men with Fe in semen was lower than expected.
What is known already
Increased levels of Fe in human semen appear to have a significant correlation with male fertility, suggesting that Fe in human seminal plasma has an important factor in male reproductive function. Fe acts as an antioxidant being a co-factor of catalasa, which protects sperm. On the other hand, elevated Fe levels are associated with sperm damage and continues to increase the lipid peroxidation that will affect the plasma membrane and the sperm motility. Most authors associate Fe with sperm motility and higher estimated fertility potential, based on standard semen parameters in fertile men, which are associated with lower levels of Fe.
Study design, size, duration
A prospective study was carried out in 102 men in a Reproduction unit in Tenerife, from February to April 2018 as a part on an epidemiologic study of environmental contaminants and male reproduction. The participant were categorized into two groups, according to the results of semen analysis following the World Health Organization guidelines: the pathological and the normal semen group that constituted the control group. The metal was determined in semen samples.
Participants/materials, setting, methods
Semen quality and levels of Fe were measured in seminal plasma on a total of 102 men attended successively, for the initial infertility evaluation, The collected samples were used for both semen analysis following the World Health Organization (WHO) guidelines and metal detection and carried out using a Makler® counting chamber (Irvine Scientific, CA) and for metals, were determined by ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometry) in semen samples.
Main results and the role of chance
The percentage of males with the presence of Fe was 97.1% and the average level were 0.6283 mg/Kg. When analyzing the relationship between the spermiogram parameters with the levels of Fe in the semen, significant differences were found. All men with a normal sperm analysis presented Fe in semen, but among men diagnosed with altered spermiogram, the percentage of men with Fe in semen (92.7%) was lower than expected (97%) (χ2 128 1 =4.59; p = 0.032). As for the concentration of Fe in spermiogram in the first quartile (25% lower), measuring 0.33 mg/Kg, more pathological samples were found than expected (X2 133 2 =6.921; p = 0.031) having a higher probability of being more pathological (52% vs 31.4%). On the other hand, men with pathological sperm concentration, have higher levels of Fe, in the fourth quartile (0.61 mg/kg), with more frequency than expected (90.6% vs 97%) (χ2 136 1 =6.48; p = 0.011). The association between BMI and the presence of Fe was statistically significant. In obese males (BMI ≥30.0 kg/m2), the percentage of men with Fe in semen (80%) was lower than expected (97%) (χ2 42 2 =11.302; p = 0.001).
Limitations, reasons for caution
The limitation of this study was the volume of semen that could be obtained for metal detection, only 0.8 mL. because the collected samples were used for both semen analysis and metal detection.
Wider implications of the findings: The determination of metals in semen opens a new field in the study of male infertility and many cases of unknown infertility could be due to metal presence or absence in semen, with the option of performing treatments.
Trial registration number
Not applicable
Focus Issue on Male Infertility