Iodine is associated to semen quality in men who undergo consultations for infertility

Thyroid disorders and pathospermia in the ART clinic patients

OBJECTIVE

Over the past decade, a decrease in the semen quality in men of reproductive age, along with an increase in the incidence of thyroid diseases among young patients have been clearly noticed. The study was designed to determine various forms of pathospermia in the ART clinic patients with thyroid disorders.

MATERIALS AND METHODS

168 men of reproductive age in infertile marriage were examined. Men with male infertility factor associated with erectile dysfunction and normospermia (9 patients, 5.3%) were excluded. The study included 159 men and the patients were divided into three groups: the 1^st study group consisted of men with non-obstructive azoospermia - 11 men (6.9%); the 2^nd study group included men with other forms of pathospermia - 38 men (23.9%) and the control group consisted of men in infertile marriage with normospermia - 110 men (69.2%). All patients had anthropometric measurements, laboratory tests, thyroid and testicular ultrasonography. Spermogram was analyzed in accordance with the WHO classification, 5^th revision, 2010.

RESULTS

Among all examined men with pathospermia (n = 49 patients), 51.02% had various thyroid disorders, while it was firstly verified in 34.7% men. In 45.5% patients with non-obstructive azoospermia, previously undiagnosed nodular goiter with normal values of thyroid-stimulating hormone and free thyroxine were found, and a significant correlation between nodular goiter and the presence of azoospermia was revealed: r = 0.610, p = .01.

CONCLUSION.

Men with various forms of pathospermia and patients of the ART clinic had higher risks of thyroid disorders than in general population that could possibly affect fertility. Patients of the ART clinic with non-obstructive azoospermia are at risk for nodular thyroid disorders, even with normal values of thyroid function tests, and require thyroid ultrasonography.

Excess iodine impairs spermatogenesis by inducing oxidative stress and perturbing the blood testis barrier

Approximately 2 billion people worldwide are susceptible to iodine deficiency. Iodine deficiency has largely been tackled by iodine fortification in salt; however indiscriminate use of iodine raises the risk of iodine toxicity. In this study, we aimed to investigate the molecular mechanisms underlying adverse effect of excess iodine on spermatogenesis. Sprague Dawley (SD) rats were orally administered with 0.7 mg potassium iodide (KI)/100 g Bw and 3.5 mg potassium iodide (KI)/100 g Bw for a period of 60 days. This resulted in significant loss of sperm count and motility. Molecular investigations provided evidence for the generation of oxidative stress with high SOD levels, reduced Nrf2, HO-1 and increased NF-kB and Follistatin. Further investigations showed increased apoptosis evidenced by reduced expression of anti-apoptotic (BCL-2, Survivin), increased expression of pro-apoptotic (Bid, Bax) markers, and increased expression of p53 and other modulators/effectors of apoptosis (cytochrome c, cleaved PARP, caspase3 and caspase9). Analysis of the blood testis barrier proteins showed reduced expression of tight junction (JAM-A, Tricellulin), ectoplasmic specialization (Integrin- β1), adherens junction (N-Cadherin, E-cadherin, β-catenin) proteins, and reduced expression of other junction protein coding genes (Claudin1, Claudin 5, Occludin, ZO-1, Testin, Fibronectin, CAR-F). Focal adhesion kinase (FAK) and key regulators of spermatogenesis (c-Kit receptor, androgen receptor) were also parallelly decreased. Further investigation showed reduced expression of germ cell proliferation and differentiation markers (PCNA, Cyclin D1, c-Kit, Cdk-4). These findings collectively explain the loss of spermatogenesis under excess iodine conditions. In conclusion, excess iodine causes loss of spermatogenesis by inducing oxidative stress and disrupting the blood testis barrier and cytoskeleton.

The association between iodine intake and semen quality among fertile men in China

BACKGROUND

Iodine intake is essential in the production of thyroid hormone but very few foods are rich in it. Iodine deficiency or excess iodine level may both lead to thyroid disorders, which further affects human fertility function. The objective of this study is to investigate the relationship between iodine intake and seminal parameters among fertile men in China.

METHODS

A total of 1098 couples were recruited by trained physicians at different family planning service stations in 2015. Semen and iodine samples were obtained from male respondents. A questionnaire survey inquired about demographic information from couples. The main outcome variables of semen quality were semen volume, semen concentration, semen motility, and sperm count, and time to pregnancy. Urinary iodine concentration (UIC) was used to measure iodine levels for male respondents. Ordinary least squared regressions and logistic regressions were performed to estimate the association between iodine intake level and semen quality parameters.

RESULTS

Male respondents with deficient or excess iodine levels had a 5% higher semen volume relative to those with optimal iodine intake (p < 0.1). Suboptimal iodine intake was negatively associated with semen concentration and semen counts (p < 0.01). Longer time of pregnancy was observed in iodine deficiency and excess group than those in the optimal group (p < 0.01).

CONCLUSION

In general, iodine deficiency and excess were both associated with decreasing semen quality parameters in male respondents.