Sperm DNA fragmentation after radioiodine treatment for differentiated thyroid cancer

Effects of radioiodine therapy on fertility indicators among men with differentiated thyroid cancer: A cohort study

Background

Following thyroidectomy, radioiodine therapy is the standard management of differentiated thyroid cancer. The effects of such treatment on testicular function remained a concern for cases and clinicians.

Objective

We aimed to observe changes in fertility indicators in men treated with ablation.

Materials and Methods

In this prospective cohort study, 18 men with differentiated thyroid cancer from June to December 2020 underwent thyroidectomy plus radioiodine therapy. Participants were grouped based on iodine dose (8 men with 30 mCi vs. 10 men with ≥ 150 mCi). Baseline values (VB) of the follicular stimulating hormone, luteinizing hormone, testosterone, and sperm analyses were measured 3 wk before iodine ablation and repeated 3 (V3) and 12 (V12) months later. They were analyzed once as a whole and once based on their groups via ANOVA and Friedman's tests where appropriate.

Results

The mean age of participants was 35.61 ± 9.74 yr. Follicular stimulating hormone levels showed a significant trend among all participants (VB: 12.51 ± 1.72, V3: 13.54 ± 1.41, and V12: 13.10 ± 1.67 IU/mL; p < 0.001). Luteinizing hormone showed a similar pattern (VB: 4.98 ± 1.27, V3: 5.65 ± 1.29, and V12: 5.21 ± 0.95 IU/mL; p < 0.001). Testosterone levels did not differ significantly from baseline. Sperm count decreased at the first checkpoint and returned to normal after 12 months (VB: 38.22 ± 19.40, V3: 32.05 ± 17.96, and V12: 36.66 ± 18.81 million/mL; p < 0.001). Sperm motility and morphology did not change significantly.

Conclusion

Our research showed that even less than 5 GBq irradiation could induce a transient testicular dysfunction in the first 3 months of therapy, but it was mostly reversible after 12 months.

Progress in Research on Sperm DNA Fragmentation

With the increasing incidence of male infertility, routine detection of semen is insufficient to accurately assess male fertility. Infertile men, who have lower odds of conceiving naturally, exhibit high levels of sperm DNA fragmentation (SDF). The mechanisms driving SDF include abnormal spermatogenesis, oxidative stress damage, and abnormal sperm apoptosis. As these factors can induce SDF and subsequent radical changes leading to male infertility, detection of the extent of SDF has become an efficient routine method for semen analysis. Although it is still debated, SDF detection has become a research hotspot in the field of reproductive medicine as a more accurate indicator for assessing sperm quality and male fertility. SDF may be involved in male infertility, reproductive assisted outcomes, and growth and development of offspring. The effective detection methods of SDF are sperm chromatin structure analysis (SCSA), terminal transferase-mediated dUTP end labeling (TUNEL) assay, single-cell gel electrophoresis (SCGE) assay, and sperm chromatin dispersion (SCD) test, and all of these methods are valuable for assisted reproductive techniques. Currently, the preferred method for detecting sperm DNA integrity is SCSA. However, the regulation network of SDF is very complex because the sperm DNA differs from the somatic cell DNA with its unique structure. A multitude of molecular factors, including coding genes, non-coding genes, or methylated DNA, participate in the complex physiological regulation activities associated with SDF. Studying SDF occurrence and the underlying mechanisms may effectively improve its clinical treatments. This review aimed to outline the research status of SDF mechanism and detection technology-related issues, as well as the effect of increased SDF rate, aiming to provide a basis for clinical male infertility diagnosis and treatment.

Impact on testicular function of a single ablative activity of 3.7 GBq radioactive iodine for differentiated thyroid carcinoma

STUDY QUESTION

What are the consequences of radioactive iodine (RAI) therapy for testicular function?

SUMMARY ANSWER

A single activity of 3.7 GBq RAI for differentiated thyroid carcinoma (DTC) treatment in young men transiently altered Sertoli cell function and induced sperm chromosomal abnormalities.

WHAT IS KNOWN ALREADY

Few studies, mainly retrospective, have reported the potential impacts of RAI on endocrine and exocrine testicular function.

STUDY DESIGN, SIZE, DURATION

A longitudinal prospective multi-center study on testicular function performed in DTC patients before a single 131I ablative activity of 3.7 GBq (V0) and at 3 months (V3) and 13 months (V13) after treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Forty male patients, aged 18-55 years, with DTC participated. Hormonal analysis included FSH, LH, testosterone and inhibin B serum levels at V0, V3 and V13. Furthermore, sperm parameters, DNA fragmentation and sperm chromosomal abnormalities were evaluated at each time points. The differences in all parameters, between V0-V3, V0-V13 and V3-V13, were analyzed, using a Wilcoxon test.

MAIN RESULTS AND THE ROLE OF CHANCE

Prior to RAI administration, all patients had normal gonadal function. At V3, a statistically significant increase in FSH levels and a decrease in inhibin B levels were observed and sperm concentration, as well as the percentage of morphologically normal spermatozoa, were significantly decreased (P < 0.0001). These modifications were transient as both sperm concentration and normal morphology rate returned to baseline values at V13. However, at this later time point, FSH and inhibin B levels were still impacted by RAI administration but remained in the normal range. Although no DNA fragmentation was observed at V3 nor V13, our study revealed a statistically significant increase in the number of sperm chromosomal abnormalities both at V3 (P < 0.001) and V13 (P = 0.01).

LIMITATIONS, REASONS FOR CAUTION

Among the 40 patients included in the study, only 24 had all the parameters available at all visits.

WIDER IMPLICATIONS OF THE FINDINGS

Prospective studies with longer term follow up would be helpful to determine whether the chromosome abnormalities persist. These studies would be required before sperm banking should be suggested for all patients. However, sperm preservation for DTC patients who require cumulative radioiodine activities higher than 3.7 GBq should be proposed.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Programme Hospitalier de Recherche Clinique, AP-HP (No. P040419). The authors report no conflict of interest in this work.

TRIAL REGISTRATION NUMBER

NCT01150318.

Effect of Amifostine on Sperm DNA Fragmentation and Testes after Radioiodine Treatment

Introduction

Radioactive iodine (RAI) is commonly used for the treatment of hyperthyroidism caused by Graves’ disease or thyroid nodules. However, information available on the impact of RAI therapy on male gonadal function is scarce. This study aimed to determine any possible damage to testicular tissue and sperm quality caused by RAI therapy, and the radioprotective effect of amifostine against such damage.

Material and Methods

In total, 36 rats were randomly allocated to three groups, including a control group, RAI group (111 MBq Iodine-131), and RAI + amifostine group (111 MBq Iodine-131 and a single dose of 200 mg/kg amifostine). Blood and epididymal sperm samples were taken for hormone analyses and the evaluation of spermatological parameters. The TUNEL assay and haematoxylin-eosin were used to stain testicular tissue samples to detect histological changes and apoptosis.

Results

The groups differed insignificantly for the testicular mass index and spermatozoa concentration. However, spermatozoa motility and percentage of viable spermatozoa were higher in the RAI + amifostine group, compared to the RAI group. Sperm DNA fragmentation and the index of apoptotic germ cells significantly decreased in the amifostine group, in comparison to the radioiodine group. While the testosterone levels showed no significant change, the follicle stimulating hormone (FSH) levels significantly decreased in the RAI + amifostine group.

Conclusion

All histopathological parameters and some spermatological parameters showed that RAI therapy caused statistically significant damage of testicular tissue and this damage was reduced by amifostine.

A systematic review on sperm DNA fragmentation in male factor infertility: Laboratory assessment

Objective

To review sperm DNA fragmentation (SDF) testing as an important sperm function test in addition to conventional semen analysis. High SDF is negatively associated with semen quality, the fertilisation process, embryo quality, and pregnancy outcome. Over recent decades, different SDF assays have been developed and reviewed extensively to assess their applicability and accuracy as advanced sperm function tests. Amongst them, the standardisation of the terminal deoxynucleotidyl transferased UTP nick-end labelling (TUNEL) assay with a bench top flow cytometer in clinical practice deserves special mention with a threshold value of 16.8% to differentiate infertile men with DNA damage from fertile men.

Materials and methods

A systematic literature search was performed through the PubMed, Medline, and ScienceDirect databases using the keywords ‘sperm DNA fragmentation’ and ‘laboratory assessment’. Non-English articles were excluded and studies related to humans were only included.

Results

Of the 618 identified, 87 studies (original research and reviews) and in addition eight book chapters meeting the selection criteria were included in this review. In all, 366 articles were rejected in the preliminary screening and a further 165 articles related to non-human subjects were excluded.

Conclusion

There are pros and cons to all the available SDF assays. TUNEL is a reliable technique with greater accuracy and as an additional diagnostic test in Andrology laboratories along with basic semen analysis can predict fertility outcome, and thus direct the choice of an assisted reproductive technology procedure for infertile couples. Also, the TUNEL assay can be used as a prognostic test and results are beneficial in deciding personalised treatment for infertile men.