Continuous improvement in the life span of TM patients allows patients to address critical issues of specific organ function. Among these hypogonadotrophic-hypogonadism (HH) and infertility are common complications, having a significant adverse impact on quality of life (QOL). While pregnancies are reported in TM women, paternity is less common in TM men, with significant gaps in our understanding of the underlying pathogenesis of male reduced fertility. Growing evidence indicates that oxidative stress negatively affects sperm quality and function, playing a central role in certain types of male infertility. In addition, abnormal low trace elements, in particular zinc, are important causes for infertility.
We hypothesized that deleterious effects of iron overload impair sperm quality beyond that of iron deposition in the pituitary and the resultant HH state, and thus aimed to evaluate potential mechanisms for infertility in TM men: Systemic and pituitary iron burden (liver iron concentration; LIC, pituitary iron by MRI, ferritin), reproductive hormones (LH, FSH) and semen fluid were measured in 7 TM men (median age 26, range 21-30 years). Semen fluid parameters included volume, sperm count, motility, DNA damage determined by DNA Fragmentation Index (DFI), concentration of glutathione (GSH), a major cellular antioxidant which plays a central role in the defense against oxidative stress, and that of pertinent metal/trace elements (iron, zinc, copper). Results were compared to normal reference and Pearson correlation analysis was performed to identify markers that best predict fertility potential and highlight pathogenesis.Sperm and semen plasma analysisLab resultsImagingPtVol. mlCount Mill/mlMotility %DFI %Zn mg/LFe mg/LGSH µmol/LLH/FSH mIU/mLFerritin ng/mLLICMRI R213.51787513141.41.189.54.9/7.96685.413.5± 0.222.500-54.42.732.20.3/0.9369625.216.4± 0.731.400-6.72.530.880.0/0.0428822.816.8± 1.442.314659.7163.02.218.661.6/2.710926.614.5± 0.951.51137---7.52.8/3.419248.4-64.594758.6120.407.54-37752016.7± 0.671.800-80.22.341.060.07/0.330002019.5± 1.2nl>2>20>50<151400.3±0.12030-60/ 0.9-15<300<39.5-13
Semen analysis showed that 5/7 (70%) had either low sperm count or complete azoospermia, and 4/7 exhibited reduced sperm motility (57%). The three patients with a measurable sperm count did not exhibit increased DNA fragmentation (normal DFI). Overall, patients had low seminal plasma GSH concentration, indicating increased oxidative stress. Seminal plasma had elevated iron concentration in 5/6 patients; zinc levels were low in 4/6, while copper was undetectable in all patients (nl 0.064 mg/L).
Patients with highest pituitary iron (2,3,7) had the lowest LH/FSH levels and azoospermia, but pituitary iron (R2) did not correlate with LH/FSH, with sperm or systemic iron measures. Seminal fluid GSH (p=0.001), iron (p=0.06), and zinc (p=0.02) inversely correlated with sperm motility. Systemic iron status, as measured by LIC and ferritin, was inversely correlated with GSH (p=0.02; 0.04, respectively) and with zinc (p=0.04; 0.04, respectively).
Our data suggest that increased free iron, iron-induced oxidative damage and low trace elements are associated with impaired semen integrity and may explain low fertility potential in TM men, beyond the expected effect of pituitary iron toxicity and HH. These abnormalities, however, did not result in sperm DNA damage, in a small analyzed sample size. Oxidative and metal profiles in seminal fluid may be a valuable tool to improve the reproductive evaluation of TM men. Anti-oxidant treatment will likely have an important role in increasing their reproductive potential.
Disclosures:
No relevant conflicts of interest to declare.
Seminal Plasma Proteomic Biomarkers of Oxidative Stress
