Impact of thyroid disease on testicular function

Eltroxin and Hesperidin mitigate testicular and renal damage in hypothyroid rats: amelioration of oxidative stress through PPARγ and Nrf2/HO-1 signaling pathway

BACKGROUND

Thyroid hormones (THs) regulate growth, development and function of different tissues. Hypothyroidism is a common clinical disorder characterized by deficiency in THs and adversely affects the development and functions of several organs. This work aimed to investigate the ameliorative effect of eltroxin (ELT), a hypothyroidism medication, and hesperidin (HSP), a flavonoid, against testicular and renal toxicity in hypothyroid rats. Twenty-four rats were divided into four groups and treated orally for 12 weeks. Group I (control), group II (hypothyroidism) received 20 mg/kg carbimazole (CBZ), group III received CBZ and 0.045 mg/kg ELT, and group IV received CBZ and 200 mg/kg HSP.

RESULTS

CBZ administration induced biochemical and histopathological changes in testis and kidney. Co-administration of ELT or HSP significantly (P < 0.05) ameliorated THs, reduced urea and creatinine while raised follicle stimulating hormone (FSH), Luteinizing hormone (LH), and testosterone in serum. Testicular and renal malondialdehyde level as a lipid peroxidation indicator, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were significantly (P < 0.05) decreased while glutathione content, glutathione peroxidase, and glutathione-s-transferase activities were significantly (P < 0.05) increased. The histopathological changes were also diminished. Decreased mRNA and protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and peroxisome proliferator-activated receptor gamma(PPARγ) in hypothyroid rats were up-regulated after ELT or HSP treatment.

CONCLUSIONS

ELT and HSP showed antioxidant and anti-inflammatory effects against CBZ-induced testicular and renal toxicity, and these effects may be promoted via activating Nrf2/HO-1 and PPARγ signaling pathways.

A comprehensive review on the decabromodiphenyl ether (BDE-209)-induced male reproductive toxicity: Evidences from rodent studies

Polybrominated diphenyl ethers (PBDEs), a class of brominated flame retardants (BFRs), are employed in various manufactured products to prevent fires, slow down their spread and reduce the resulting damages. Decabromodiphenyl ether (BDE-209), an example of PBDEs, accounts for approximately 82 % of the total production of PBDEs. BDE-209 is a thyroid hormone (TH)-disrupting chemical owing to its structural similarity with TH. Currently, increase in the level of BDE-209 in biological samples has become a major issue because of its widespread use. BDE-209 causes male reproductive toxicity mainly via impairment of steroidogenesis, generation of oxidative stress (OS) and interference with germ cell dynamics. Further, exposure to this chemical can affect metabolic status, sperm concentration, epigenetic regulation of various developmental genes and integrity of blood-testis barrier in murine testis. However, the possible adverse effects of BDE-209 and its mechanism of action on the male reproductive health have not yet been critically evaluated. Hence, the present review article, with the help of available literature, aims to elucidate the reproductive toxicity of BDE-209 in relation to thyroid dysfunction in rodents. Further, several crucial pathways have been also highlighted in order to strengthen our knowledge on BDE-209-induced male reproductive toxicity. Data were extracted from scientific articles available in PubMed, Web of Science, and other databases. A thorough understanding of the risk assessment of BDE-209 exposure and mechanisms of its action is crucial for greater awareness of the potential threat of this BFR to preserve male fertility.

Effects of perchlorate, nitrate, and thiocyanate exposures on serum total testosterone in children and adolescents

Perchlorate, nitrate, and thiocyanate are common thyroid disruptors in daily life and alter testosterone levels in animals. However, little is known about the effects of perchlorate, nitrate, and thiocyanate on serum total testosterone (TT) in the general population. The study was designed to assess the associations between urinary levels of perchlorate, nitrate, and thiocyanate and serum total testosterone (TT) in the general population. The present study utilized data from the 2011-2016 National Health and Nutritional Examination Survey (NHANES). A total of 6201 participants aged 6-79 with information on urinary perchlorate, nitrate, thiocyanate, and serum total testosterone were included. We conducted multiple linear regression models and Bayesian Kernel Machine Regression (BKMR) models to estimate the associations by sex-age groups. Children (ages 6-11) have higher levels of perchlorate and nitrate than the rest. After adjusting for covariates, urinary perchlorate was significantly negatively associated with serum TT in male adolescents (β = -0.1, 95 % confidence interval: -0.2, -0.01) and female children [-0.13, (-0.21, -0.05)]. Urinary nitrate was significantly negatively associated with serum TT in female children, while urinary thiocyanate was significantly positively associated with serum TT in female adults aged 20 to 49 [0.05 (0.02, 0.08)]. BKMR analysis indicated that no other interactions were found between urinary perchlorate, nitrate, and thiocyanate. Our findings suggested that urinary perchlorate, nitrate, and thiocyanate levels may relate to serum total testosterone levels in specific sex-age groups. We identified male adolescents and female children as are most sensitive subgroups where testosterone is susceptible to interference.

The role of thyroid function in female and male infertility: a narrative review

PURPOSE

We herein aimed to review the new insights into the impact of impaired thyroid function on male and female fertility, spacing from spontaneous pregnancy to ART, with the objective of providing an updated narrative revision of the literature.

METHODS

This narrative review was performed for all available prospective, retrospective and review articles, published up to 2021 in PubMed. Data were extracted from the text and from the tables of the manuscript.

RESULTS

Thyroid dysfunction is frequently associated with female infertility, whereas its link with male infertility is debated. Female wise, impaired function is detrimental to obstetric and fetal outcomes both in spontaneous pregnancies and in those achieved thanks to assisted reproduction technologies (ART). Furthermore, the reference range of TSH in natural pregnancy and ART procedures has recently become a matter of debate following recent reports in this field. On the other hand, the impact of thyroid function on the male reproductive system is less clear, although a possible role is suggested via modulation of Sertoli and Leydig cells function and spermatogenesis.

CONCLUSION

Thyroid function should be carefully monitored in both male and female, in couples seeking spontaneous pregnancy as well as ART, as treatment is generally immediate and likely to improve chances of success.

Thymoquinone protects the testes of hypothyroid rats by suppressing pro-inflammatory cytokines and oxidative stress and promoting SIRT1 testicular expression

Background: Hypothyroidism has been linked to many testicular structural and dysfunctional changes in males. Thymoquinone (TQ) has shown a potent testicular protective effect through its antioxidant, anti-inflammatory, antiapoptotic, fertility-enhancing, and endocrine modulatory activities. Objectives: This study aimed to investigate the efficacy of TQ in preserving the testicular structure of a model of experimentally induced hypothyroidism in rats and identify the mechanism behind this effect. Materials and methods: Propylthiouracil (PTU) was used to induce hypothyroidism in adult male Wistar rats, who were then treated with TQ (50 mg/kg/body weight) for 4 weeks and compared to the untreated rats. Thyroid hormonal profile, oxidants/antioxidants profile, and serum testosterone levels were assessed. Gene expression and immune expression of SIRT1 and pro-inflammatory cytokines TNF-α and NF-κB were also assessed in the testicular tissue. Results: TQ administration successfully improved PTU-induced disturbance in the thyroid hormonal profile (T3, T4, and TSH), serum testosterone level, and pancreatic antioxidants compared to the untreated hypothyroid group. TQ significantly downregulated (p = 0.001, p ˂ 0.001) TNF-α and NF-κB transcription, while it significantly upregulated (p = 0.01) SIRT1 transcription in the testes of hypothyroid rats. TQ markedly relieved the histopathological testicular changes induced by PTU and significantly increased (p = 0.002, p = 0.01) the sectional area of seminiferous tubules and germinal epithelial height, respectively. TUNEL-positive apoptotic germinal cells were significantly decreased (p ˂ 0.001), while PCNA-positive proliferating germinal cells and androgen receptor expression were significantly increased (p ˂ 0.001) in the testes of TQ-treated hypothyroid rats. Conclusion: Thymoquinone could limit the hypothyroidism-induced structural changes in the testis, mostly through the upregulation of SIRT1 expression, which seems to mediate its promising antioxidant, anti-inflammatory and antiapoptotic effects that were evident in this study. Therefore, TQ is recommended as an adjuvant safe supplement in managing hypothyroidism, especially in males.

Mechanisms of Male Reproductive Toxicity of Polybrominated Diphenyl Ethers

Polybrominated diphenyl ethers (PBDE) are a group of flame retardants used in a variety of artificial materials. Despite being phased out in most industrial countries, they remain in the environment and human tissues due to their persistence, lipophilicity, and bioaccumulation. Populational and experimental studies demonstrate the male reproductive toxicity of PBDEs including increased incidence of genital malformations (hypospadias and cryptorchidism), altered weight of testes and other reproductive tissues, altered testes histology and transcriptome, decreased sperm production and sperm quality, altered epigenetic regulation of developmental genes in spermatozoa, and altered secretion of reproductive hormones. A broad range of mechanistic hypotheses of PBDE reproductive toxicity has been suggested. Among these hypotheses, oxidative stress, the disruption of estrogenic signaling, and mitochondria disruption are affected by PBDE concentrations much higher than concentrations found in human tissues, making them unlikely links between exposures and adverse reproductive outcomes in the general population. Robust evidence suggests that at environmentally relevant doses, PBDEs and their metabolites may affect male reproductive health via mechanisms including AR antagonism and the disruption of a complex network of metabolic signaling.

Study on the Interaction between Serum Thyrotropin and Semen Parameters in Men

The effect of thyroid function on semen parameters has been studied in pathological conditions in small studies. With this research work, we aimed to study thyroid hormone effects on semen parameters in 130 men who were evaluated for couple subfertility. Our study was cross-sectional. We noted semen volume, sperm concentration, total sperm count, testosterone levels and thyrotropin (TSH) levels. The analysis included ordinary least squares regression (OLS-R), quantile regression (QR) and segmented line regression (SR). Using OLS-R, a weak negative correlation was found between the logTSH levels and semen volume (r = −0.16, r² = 0.03, p = 0.05). In Q-R, each incremental unit increase in logTSH decreased the mean semen volume between −0.78 ± 0.44 and −1.33 ± 0.34 mL (40–60th response quantile) and between −1.19 ± 0.71 and −0.61 ± 0.31 mL (70–90th response quantile) (p = 0.049). With SR, a biphasic relationship of sperm concentration with TSH was noted (positive turning to negative, peaking at TSH = 1.22 μIU/mL). Thus, a weak negative association between the TSH levels and semen volume was noted, showing a trough within the usual normal range for TSH. Moreover, a biphasic relationship between the sperm concentration and TSH was also noted, peaking at approximately mid-normal TSH levels. Based on our results, TSH explained slightly less than 3% of the variation in semen volume and 7% of the sperm concentration (thus, other factors, which were not studied here, have a more important effect on it).

Pathogenesis of Autoimmune Male Infertility: Juxtacrine, Paracrine, and Endocrine Dysregulation

According to global data, there is a male reproductive potential decrease. Pathogenesis of male infertility is often associated with autoimmunity towards sperm antigens essential for fertilization. Antisperm autoantibodies (ASAs) have immobilizing and cytotoxic properties, impairing spermatogenesis, causing sperm agglutination, altering spermatozoa motility and acrosomal reaction, and thus preventing ovum fertilization. Infertility diagnosis requires a mandatory check for the ASAs. The concept of the blood–testis barrier is currently re-formulated, with an emphasis on informational paracrine and juxtacrine effects, rather than simple anatomical separation. The etiology of male infertility includes both autoimmune and non-autoimmune diseases but equally develops through autoimmune links of pathogenesis. Varicocele commonly leads to infertility due to testicular ischemic damage, venous stasis, local hyperthermia, and hypoandrogenism. However, varicocelectomy can alter the blood–testis barrier, facilitating ASAs production as well. There are contradictory data on the role of ASAs in the pathogenesis of varicocele-related infertility. Infection and inflammation both promote ASAs production due to “danger concept” mechanisms and because of antigen mimicry. Systemic pro-autoimmune influences like hyperprolactinemia, hypoandrogenism, and hypothyroidism also facilitate ASAs production. The diagnostic value of various ASAs has not yet been clearly attributed, and their cut-levels have not been determined in sera nor in ejaculate. The assessment of the autoimmunity role in the pathogenesis of male infertility is ambiguous, so the purpose of this review is to show the effects of ASAs on the pathogenesis of male infertility.

Spermatozoa retrieval in azoospermia and expression profile of JMJD1A, TNP2, and PRM2 in a subset of the Karachi population

BACKGROUND

The difficulties encountered in surgical spermatozoa retrieval for intracytoplasmic sperm injection procedure in azoospermic men have stressed the dire need for a robust biomarker for the prediction of spermatozoa retrieval. Data have highlighted the role of JMJD1A (Jumonji domain-containing 1A), a histone H3K9 demethylase, and other nuclear proteins, protamines (PRM) and transition nuclear proteins (TNP), as biomarkers in male infertility.

OBJECTIVE

To access successful spermatozoa retrieval at the time of intracytoplasmic sperm injection by evaluating the mRNA expression profile of JMJD1A, TNP, and PRM in testicular tissue.

MATERIALS/METHODS

About 100 azoospermic patients, who visited the Australian Concept Infertility Medical Center, Karachi for spermatozoa retrieval by testicular sperm extraction or microsurgical testicular sperm extraction participated in the study. mRNA expression of the JMJD1A, TNP1, TNP2, PRM1, and PRM2 genes was determined. Patients were categorized into successful spermatozoa retrieval (n = 42) group and unsuccessful spermatozoa retrieval (n = 58) group.

RESULTS

Azoospermic men in successful spermatozoa retrieval had significantly increased expression of JMJD1A, TNP2, and PRM2. The hormonal parameters - follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone were significantly higher in unsuccessful spermatozoa retrieval. Multivariate analysis showed a significant association between JMJD1A, TNP2, PRM2, and successful spermatozoa retrieval. The area under the receiver operating characteristics curve showed a significant discriminatory ability to predict the spermatozoa retrieval outcome in azoospermic patients for mRNA expression of JMJD1A, TNP2, and PRM2 was 71, 72, and 73%, respectively. The area under the curve for follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone was 0.67, 0.81, and 0.65, respectively.

DISCUSSION

Our study demonstrates that the mRNA expression profile of JMJD1A, TNP2, and PRM2 along with hormonal parameters, is a useful marker to assess the probability of spermatozoa retrieval before intracytoplasmic sperm injection intervention.

CONCLUSION

The probability of spermatozoa retrieval in azoospermic patients is increased when the mRNA expression profile of JMJD1A, TNP2, and PRM2 in testicular tissue is increased.

The probable destructive mechanisms behind COVID-19 on male reproduction system and fertility

PURPOSE

The present study aims to summarize the current understanding of probable mechanisms and claims of adverse effects of SARS-CoV-2 on male fertility potential.

METHODS

Our search was including original articles, reviews, guidelines, letters to the editor, comments on guidelines, and editorials, regarding the male reproductive system. We used the words SARS-CoV-2, coronavirus, severe acute respiratory syndrome coronavirus 2, "2019 ncov," testis, sperm, male factor infertility, fertility treatment, semen, assisted reproductive technology (ART), sexual transmission, and ACE2.

RESULTS

Data showed coronavirus affects men more than women because of more expression of 2019 nCoV receptors (ACE2 and TMPRSS2) in testicular cells. Also, "Bioinformatics Analysis" suggests that sperm production may be damaged, since "Pseudo Time Analysis" has shown disruption in spermatogenesis. "Gene Ontology" (GO) showed an increase in viral reproduction and a decrease in sperm production-related terms. Recently, SARS-COV-2 mRNA and protein were detected in the semen of patients that had recovered from SARS-CoV-2 infection. Therefore, the probable disruption of blood-testis barrier (BTB) in febrile diseases is suspected in the acute phase of the disease enabling viral entry into the testes. Not only is spermatogenesis disturbed, but also disturbs gonadotropin, androgens, and testosterone secretion during SARS-CoV-2 infection. No sexual transmission has been reported yet; however, detection of the virus in semen still makes the sexual transmission an open question.

CONCLUSION

There is a concern that male fertility may be disturbed after the SARS-CoV-2 infection. Therefore, follow-up of the reproductive functions and male fertility may be necessary in recovered cases, especially in aged men.

A hazard evaluation of the reproductive/developmental toxicity of cobalt in medical devices

Cobalt (Co) is an essential element with human exposure occurring from the diet, supplement ingestion, occupational sources, and medical devices. The European Chemical Agency (ECHA) recently voted to classify Co metal as a Reproductive Hazard Category 1B; presumed human reproductive toxicant due to adverse testicular effects in male rodents. A weight of evidence evaluation of the preclinical reproductive and developmental toxicity studies and available clinical data was performed to critically evaluate the relevance of this proposed classification for Co in medical devices. Reproductive responses to Co are limited to the male testes and sperm function following high systemic exposure in rodents, only at Co concentrations/doses that result in overt toxicity (i.e., above the maximum tolerable dose (MTD)). The potential mechanisms of Co reproductive/developmental toxicity, including its indirect mode of action in the testes and relevance to humans, are discussed. The available preclinical and clincial evidence suggests that it would be more appropriate to classify Co as a Reproductive Hazard Category 2 compound: suspected human reproductive toxicant and, in the case of Co-containing medical devices, it should not be considered a reproductive hazard.

Thyroid function, sex hormones and sexual function: a Mendelian randomization study

Hypothyroidism and hyperthyroidism are observationally associated with sex hormone concentrations and sexual dysfunction, but causality is unclear. We investigated whether TSH, fT4, hypo- and hyperthyroidism are causally associated with sex hormones and sexual function. We used publicly available summary statistics from genome-wide association studies on TSH and fT4 and hypo- and hyperthyroidism from the ThyroidOmics Consortium (N ≤ 54,288). Outcomes from UK Biobank (women ≤ 194,174/men ≤ 167,020) and ReproGen (women ≤ 252,514) were sex hormones (sex hormone binding globulin [SHBG], testosterone, estradiol, free androgen index [FAI]) and sexual function (ovulatory function in women: duration of menstrual period, age at menarche and menopause, reproductive lifespan, and erectile dysfunction in men). We performed two-sample Mendelian randomization (MR) analyses on summary level, and unweighted genetic risk score (GRS) analysis on individual level data. One SD increase in TSH was associated with a 1.332 nmol/L lower (95% CI: - 0.717,- 1.946; p = 2 × 10^-5) SHBG and a 0.103 nmol/l lower (- 0.051,V0.154; p = 9 × 10^-5) testosterone in two-sample MR, supported by the GRS approach. Genetic predisposition to hypothyroidism was associated with decreased and genetic predisposition to hyperthyroidism with increased SHBG and testosterone in both approaches. The GRS for fT4 was associated with increased testosterone and estradiol in women only. The GRS for TSH and hypothyroidism were associated with increased and the GRS for hyperthyroidism with decreased FAI in men only. While genetically predicted thyroid function was associated with sex hormones, we found no association with sexual function.

Impaired sperm quantity and motility in adult rats following gestational and lactational exposure to environmentally relevant levels of PBDE-47: A potential role of thyroid hormones disruption

Polybrominated diphenyl ethers (PBDEs) are flame retardants and the congener 2, 2', 4, 4'-tetrabromodiphenyl ether (PBDE-47) is capable of inducing thyroid endocrine disruption and developmental toxicity. However, little is known about whether developmental PBDE-47 exposure-elicited alterations in semen quality is associated with thyroid hormones (THs) perturbation. In this research, we sought to explore the impacts of gestational and lactational PBDE-47 exposure on adult sperm quantity and motility, and its link with THs levels. For this purpose, female Sprague-Dawley rats were administered environmentally relevant PBDE-47 levels (0.1, 1.0, 10 mg/kg/day) by oral gavage from prepregnancy through lactation cessation to achieve early-life exposure of offspring and to mimic the actual exposure. Sperm quantity and motility together with serum THs levels from male offspring were determined on postnatal day 88. In utero and lactational exposure to PBDE-47 boosted the weight gain while reduced the relative testis weight in adult male offspring. These were accompanied with the reductions in sperm counts (total and living sperm counts), the percentage of progressive sperm motility, sperm velocities (curvilinear velocity, straight-line velocity and average path velocity), motion path (beat cross frequency, linearity and wobble) and linear motile sperm parameters (count, motility and concentration). Further studies identified that the levels of serum triiodothyronine (T₃) were increased by PBDE-47 exposure and negatively associated with those differential semen parameters on quantity and motility. Collectively, our results indicate that exposure to low-level PBDE-47 during early-life development impairs semen quality in adult rats, which could be mediated partially by abnormal T₃ levels.

Paternal Subclinical Hypothyroidism Affects the Clinical Outcomes of In Vitro Fertilization/Intracytoplasmic Sperm Injection

Background: Maternal subclinical hypothyroidism (SCH) is a risk factor for adverse pregnancy outcomes. However, it is still unclear whether SCH affects male fertility. The aim of this study was to determine the association between paternal SCH and clinical outcomes after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Methods: This retrospective study included 2511 couples with paternal euthyroidism (n = 2282) or SCH (n = 229) who visited our clinic for infertility treatment between April 1, 2017, and September 30, 2019. The primary outcomes were the fertilization rate and clinical pregnancy rate; the secondary outcomes were the good-quality embryo rate, blastocyst formation rate, implantation rate, and early miscarriage rate. These outcomes were compared between the euthyroid and the SCH groups after adjusting for various potential confounders. Results: The mean paternal ages in the euthyroid and SCH groups were 34.5 and 36.0 years, respectively (p = 0.002). Semen parameters and sperm DNA fragmentation index were similar between the two groups (all p > 0.05). The adjusted fertilization (0.69 vs. 0.71, p = 0.30), good-quality embryo (0.49 vs. 0.52, p = 0.31), blastocyst formation (0.51 vs. 0.53, p = 0.57), and early miscarriage (0.11 vs. 0.10, p = 0.81) rates were also similar between the two groups. There was a significantly decreased adjusted clinical pregnancy rate [confidence interval, CI] and implantation rate [CI] in the paternal SCH group compared with the euthyroid group (0.32 [0.26-0.40] vs. 0.42 [0.40-0.45], p = 0.009 for the clinical pregnancy rate; 0.24 [0.19-0.29] vs. 0.29 [0.27-0.31], p = 0.037 for the implantation rate). Stratified analysis indicated that these differences were only significant in men aged ≥35 years (p = 0.009 and 0.022, respectively) and not in men <35 years (p = 0.39 and 0.45, respectively). Conclusions: Paternal SCH was associated with worse clinical outcomes after IVF/ICSI, whereas this detrimental impact was only present in males ≥35 years old. Prospective studies and basic research are warranted to confirm these results and to clarify the mechanisms underlying these associations, respectively.

Comparison of proteomic profiles from the testicular tissue of males with impaired and normal spermatogenesis

In this study, we aimed to explore the potential differences in proteomic profiles from the testicular tissue of azoospermatic men with impaired spermatogenesis and normal spermatogenesis. Isobaric tags for relative and absolute quantitation (iTRAQ) labeled technology and LC-MS/MS technology were used to identify differentially expressed proteins. Potential functions of differentially expressed proteins were predicted using gene ontology (GO) and the Kyoto encyclopedia of genes and genomes (KEGG). Immunohistochemistry (IHC) and western blot (WB) were used to verify the differentially expressed proteins. A protein-protein interaction (PPI) network was built to outline the regulatory network of differentially expressed proteins. A total of 3,945 proteins were identified in men with normal and impaired spermatogenesis. Of these, 116 proteins were differentially expressed in men with impaired spermatogenesis: 39 were upregulated and 77 were downregulated. Furthermore, we found that these differentially expressed proteins were mainly involved in the cellular component, which may be mainly associated with the spliceosome, ribosome, and thyroid hormone synthesis signaling pathways. The spliceosome- and ribosome-associated proteins YBX1, FBL, and HNRNPU were downregulated. And the proteomic profile of testicular tissue in men with impaired spermatogenesis is different from that of men with normal spermatogenesis. For this reason, differentially expressed proteins such as YBX1, FBL and HNRNPU might be involved in the pathology of spermatogenesis dysfunction.Abbreviations: iTRAQ: Isobaric tags for relative and absolute quantitation;GO: Gene ontology; KEGG: Kyoto encyclopedia of genes and genomes; IHC: Immunohistochemistry; WB: Western blot; PPI: Protein-protein interaction; ICSI: Intracytoplasmic sperm injection; BP: Biological process; CC: Cellular components; MF: Molecular function; snoRNA: Small nucleolar RNA; snRNA: Small nuclear RNA; LC-MS/MS: Liquid chromatography and MS/MS analysis; BSA: Bovine serum albumin; SD: Spermatogenic dysfunction; micro-TESE: Testicular microscopic sperm extraction.

Nonsurgical Management of Oligozoospermia

Male infertility secondary to oligozoospermia is surprisingly common. Although a majority of cases are idiopathic, oligozoospermia can be caused by endocrine dysfunction, anatomic abnormalities, medications, or environmental exposures. The work-up includes excluding reversible factors such as hormonal deficiency, medication effects, and retrograde ejaculation and identifying any underlying genetic syndrome and treating reversible medical causes. If no reversible cause is found, appropriate referrals to urology and assisted reproductive technology should be initiated. Lastly, clinicians should be aware of and respond to the psychological and general health ramifications of a diagnosis of oligozoospermia as part of the comprehensive care of men and couples struggling with a diagnosis of infertility.

Diagnosis and Management of Hypothyroidism in Gulf Cooperation Council (GCC) Countries

Hypothyroidism is one of the most common chronic endocrine conditions. However, as symptoms of hypothyroidism are non-specific, up to 60% of those with thyroid dysfunction are unaware of their condition. Left untreated, hypothyroidism may contribute to other chronic health conditions. In the Arabian Gulf States, hypothyroidism is thought to be common, but is underdiagnosed, and management approaches vary. An advisory board of leading Saudi endocrinologists and policy advisers was convened to discuss and formulate recommendations for the diagnosis and management of hypothyroidism in Saudi Arabia based on their clinical expertise. The final document was shared with leading endocrinologists from the other Gulf  Cooperation Council (GCC) and aconsensus report was generated and summerized in this article. While there is no consensus regarding population screening of hypothyroidism, current recommendations suggest screening patients with risk factors, including those with a history of head or neck irradiation, a family history of thyroid disease or pharmacological treatment that may affect thyroid function. Evidence from a cross-sectional study in Saudi Arabia suggests screening the elderly (> 60 years), at least in the primary care setting. In Saudi Arabia, the incidence of congenital hypothyroidism is approximately 1 in every 3450 newborns. Saudi nationwide population prevalence data are lacking, but a single-centre study estimated that the prevalence of subclinical hypothyroidism in the primary care setting was 10%. Prevalence rates were higher in other cross-sectional studies exclusively in women (13-35%). The recommendations included in this  article aim to streamline the diagnosis and clinical management of hypothyroidism in the GCC, especially in the primary care setting, with the intention of improving treatment outcomes. Further study on the incidence, prevalence and risk factors for, and clinical features of, hypothyroidism in the GCC countries is required.

Low CSF/serum ratio of free T4 is associated with decreased quality of life in mild hypothyroidism - A pilot study

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General health, according to the Likert scale, was considerable affected even in mild hypothyroidism.

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The level of T4 in the brain, expressed as the CSF/serum f-T4 ratio, was associated with decreased general health.

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Depressive symptoms, according to the MADRS scale, correlated with the CSF/serum f-T4 ratio.

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T4 might have a direct effect in the brain, and not only as a storage hormone for the more active T3.

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Further studies on pharmacokinetics of CSF-thyroxine might be of benefit especially in patients not feeling well.

Background & Objective

Patients with mild hypothyroidism often are depressed and have impaired quality of life despite serum free-T4 and T3 within reference values. Therefore, we investigated whether their symptoms were dependent on the concentrations of free -T4 and T3 in the circulation and cerebrospinal fluid (CSF).

Methods

Twenty-five newly diagnosed, untreated hypothyroid subjects and as many age- and sex-matched healthy controls were investigated. Blood and CSF sampling was performed in the morning after an overnight fast. Quality of life (QoL) was assessed by a Likert scale. In the hypothyroid subjects, the MADRS rating scale was also used to evaluate symptoms of depression. Furthermore, the results obtained by the questionnaires were related to serum and CSF levels of free- T4 and T3 as well as the ratios between them in CSF and in serum.

Results

Self-reported health was considerably lower in hypothyroid subjects. MADRS was considerably higher than the normal range for healthy individuals. Low CSF/serum free-T4 ratio was correlated with an increased depressed state according to MADRS (p < 0.01), and in addition, CSF/serum free-T4 ratio correlated positively with the self-reported general health Likert scale (p < 0.05). Concentrations of TSH, or free-T3 in serum or CSF, were not associated with an increased depressed state or self-reported general health.

Conclusions

Low CSF/serum ratio of free-T4 was correlated with impaired general health and mood, in contrast to serum measurements not showing any correlations. These findings might partly explain why some patients with hypothyroidism suffer from mental symptoms, despite adequate serum levels of free-T4. However, the findings need to be confirmed in further and larger studies.

Imbalanced testicular metabolism induced by thyroid disorders: New evidences from quantitative proteome

Thyroid dysfunctions, such as hypothyroidism and hyperthyroidism, are the second most prevalent endocrinopathies and are associated to reproductive disorders in men. Several genes are differentially modulated by thyroid hormones in testes and imbalances in thyroid hormone levels are also associated to alterations on sperm functionality. Imbalances on antioxidant defense mechanism and stress oxidative have been pointed out as the main factors for the impairments on male reproductive function. To clarify this issue, we investigated the expression and activity of antioxidant enzymes in testis, followed by their proteomic profile in attempt to characterize the mechanisms involved in the alterations induced by hypo- or hyperthyroidism in adult male rats. Hypothyroidism reduced the Gsr transcript expression and the activity of CAT and GSR enzymes, while the hyperthyroidism reduced the Gpx4 var2 transcript expression. Among 1082 identified proteins, 123 and 37 proteins were downregulated by hypothyroidism compared to euthyroid and hyperthyroid condition, respectively, being 36 proteins commonly reduced in both comparisons and one exclusively in hypo-hyperthyroidism comparison. A network containing 29 nodes and 68 edges was obtained in protein-protein interaction analysis and the functional enrichment analysis of differentially expressed proteins revealed significant alterations for several functions in hypo-euthyroid and hypo-hyperthyroid comparisons, such as ATP metabolic process, coenzyme binding, sperm part, peroxiredoxin activity, mitochondrial protein complex, intramolecular oxidoreductase activity, binding of sperm to zona pellucida, glutathione transferase activity, response to testosterone. Thus, there is a correlation between thyroid disorders and impaired antioxidant defense mechanism, resulting in reproductive dysfunctions, as infertility, mainly observed in hypothyroidism.

The impact of thyroid diseases starting from birth on reproductive function

The aim of this review is to provide relevant information regarding the impact of thyroid disease, starting from birth and mainly concerning hyperthyroidism and hypothyroidism, on reproduction. Hyperthyroidism occurs much less commonly in children than hypothyroidism, with Graves' disease (GD) being the most common cause of thyrotoxicosis in children. Children born with neonatal GD have no defects in the reproductive system that could be related to hyperthyroidism. Current treatment options include antithyroid drugs (ATD), surgery, and radioactive iodine (RAI). In males, normal thyroid function seems important, at least in some parameters, for maintenance of semen quality via genomic or non-genomic mechanisms, either by locally acting on Sertoli cells, Leydig cells, or germ cells, or by affecting crosstalk between the HPT axis and the HPG axis. Sexual behavior may also be affected in thyroxic men, although many of these patients may have normal free testosterone levels. In women, menstrual irregularities are the most common reproduction-related symptoms in thyrotoxicosis, while this disorder is also associated with reduced fertility, although most women remain ovulatory. An increase in sex hormone-binding globulin (SHBG) and androgens, thyroid autoimmunity, and an impact on uterine oxidative stress are the main pathophysiological mechanisms which may influence female fertility. Thyroid hormones are responsible for normal growth and development during pre- and postnatal life, congenital hypothyroidism (CH) being the most common cause of neonatal thyroid disorders, affecting about one newborn infant in 3500. The reproductive tract appears to develop normally in cretins. Today, CH-screening programs allow for early identification and treatment, and, as a result, affected children now achieve normal or near-normal development. Hypothyroidism in males is associated with decreased libido or impotence. Although little is currently known about the effects of hypothyroidism on spermatogenesis and fertility, it has been established that sperm morphology and motility are mainly affected. In women of reproductive age, hypothyroidism results in changes in cycle length and amount of bleeding. Moreover, a negative effect on fertility and higher miscarriage rates has also been described.

Interventions to Prevent Sperm DNA Damage Effects on Reproduction

Excessive oxidation and antioxidant imbalance resulting from several conditions may cause sperm DNA damage, which, in turn, affect male fertility, both natural and assisted. Sperm DNA damage transferred to the embryo might also affect the health of offspring. Several conditions associated with excessive oxidative stress are modifiable by the use of specific treatments, lifestyle changes, and averting exposure to environmental/occupational toxicants. Here, we discuss the strategies to reduce sperm DNA damage with a focus on clinical and surgical interventions.

Thyroid Hormones and Spermatozoa: In VitroEffects on Sperm Mitochondria, Viability and DNA Integrity

The aim of this study wasto assess the in vitro effects of levothyroxine (LT4) on conventional and bio-functional sperm parameters and its implications on fertility. Patients with male idiopathic infertility were enrolled and subjected to examination of the seminal fluid and capacitation according to the WHO 2010 criteria and flow cytometric sperm analysis for the evaluation of bio-functional sperm parameters. LT4 significantly increased the percentage of spermatozoa with high mitochondrial membrane potential (MMP), decreased the percentage of spermatozoa with low MMP and increased sperm motility already at a concentration of 0.9 pmol L⁻¹. Therefore, LT4 significantly reduced sperm necrosis and lipid peroxidation ameliorating chromatin compactness. These effects of LT4 were evident at a concentration of 2.9 pmol L⁻¹, close to the physiological free-thyroxine (FT4) concentrations in the seminal fluid of euthyroid subjects. We showed a beneficial role of thyroid hormones on sperm mitochondrial function, oxidative stress and DNA integrity. The results of this in vitro study could have a clinical application in patients with idiopathic infertility, clarifying the role of thyroid function on male fertility.

Thyroid dysfunction and semen quality

Thyroid hormones act on testis in multiple ways and exert their effect on different cell types, including Leydig and Sertoli cells, and germ cells. An excess or deficit of thyroid hormones results in alterations of testis function, including semen abnormalities. More frequently, hyperthyroidism has been associated with reduced semen volume and reduced sperm density, motility, and morphology, whereas hypothyroidism is associated with reduced sperm morphology. Therefore, thyroid function tests should be part of the diagnostic workup of the infertile man. This article is aimed at (1) elucidating how hyperthyroidism and hypothyroidism lead to a reduction in semen quality, briefly reviewing the current literature on murine models and humans, and (2) pinpointing the limitations of the studies carried out so far and identifying new perspectives for future research.

Thyroid Hormone Deiodination and Action in the Gonads

Alterations in thyroid hormone (TH) status during developmental or adult age are associated with abnormal gonadal development and function in human and animal models. In the developing testis, aberrant levels of TH action lead to disruptions in cell proliferation and differentiation, ultimately influencing testicular size, spermatogenesis, steroidogenesis and male fertility. Recent work is increasingly identifying the systems and signaling pathways in gonadal cells that are affected by TH, as well as delineating the major factors that determine TH signaling in gonadal tissue. The TH receptor alpha, the monocarboxylate transporter 8 and the type 3 deiodinase appear to be major contributors to the timely regulation of TH action in the developing testis.

Triiodothyronine differentially modulates the LH and FSH synthesis and secretion in male rats

Hypothyroidism and thyrotoxicosis produce adverse effects in male reproduction by unknown mechanisms. We investigated whether triiodothyronine (T3) modulates luteinizing hormone (LH) and follicle stimulating hormone (FSH) synthesis/secretion, by inducing different thyroid states. In hypothyroidism, the content of Lhb and Fshb mRNAs was increased, while their association to ribosomes and the protein content were reduced and the serum LH and FSH concentrations were augmented and decreased, respectively. Thyrotoxicosis reduced Lhb mRNA and LH serum concentration, and increased Lhb mRNA translational rate. The Fshb mRNA content and its association to ribosomes were also increased, whereas FSH serum concentrations were comparable to euthyroid levels. Acute T3 treatment decreased the total content of Lhb and Fshb mRNAs, and increased their association to ribosomes, as well as the LHB and FSHB contents in secretory granules. This study shows that T3 acts on gonadotrophs, resulting in direct effects on LH and FSH synthesis/secretion of male rats, suggesting that some reproductive disorders observed in men may be associated with thyroid hormone imbalances.