Thyroid hormone receptors and ligands, tissue distribution and sexual behavior

Efficacy and safety of PDE5 inhibitors in middle-aged and old patients with and without hypogonadism

PURPOSE

Although several reviews have evaluated the use of PDE5 inhibitors (PDE5i) for treating erectile dysfunction (ED), their specific use in middle-aged and old patients has not been fully evaluated. Given that elderly patients with ED often have a complex combination of systemic and sexual health risk factors, the safety and efficacy of PDE5i in such a context are hereby reviewed.

MATERIALS AND METHODS

A thorough examination of existing literature has been conducted on PubMed.

RESULTS

PDE5i has good safety and efficacy, but the situation is more complex for patients with hypogonadism than those with normal testosterone levels, with reduced responsiveness to PDE5i. In this case, combination therapy with testosterone is recommended, safe and effective.

CONCLUSIONS

Eliminating or reducing reversible risk factors and controlling or slowing the development of irreversible factors is an important foundation for using PDE5i to treat ED in all patients, especially middle-aged and elderly ones.

Female Mice Exposed to Pyriproxyfen Since Prepuberty Showed Reproductive Impairment During Sexual Maturity and Increased Fetal Death in Their Offspring

Pyriproxyfen (PPF) is an insecticide used in agriculture, which is approved for use in drinking water tanks for human consumption. However, some studies indicate that it may act as an endocrine disruptor and affect nontarget organisms. This study aimed to evaluate the effects of PPF on reproduction and general health status in female mice exposed from pre-puberty to adulthood. In the first experiment, females were treated by gavage from postnatal day (PND) 23 to (PND) 75 and were distributed into three experimental groups: control (vehicle), PPF 0.1 mg/kg, and PPF 1 mg/kg. Female mice were assessed for the age of puberty onset, body mass, water and food consumption, and the estrous cycle. On PDN 75, a subgroup was euthanized, when vital and reproductive organs were collected and weighed. The thyroid, ovary, and uterus were evaluated for histomorphometry. The other subgroup was assessed in relation to reproductive performance and fetal parameters. In a second experiment, the uterotrophic assay was performed with juvenile females (PND 18) using doses of 0.01, 0.1, or 1 mg/kg of PPF. PPF treatment reduced thyroid mass and increased liver mass. Furthermore, there was an increase in ovarian interstitial tissue and, in the uterus, a decrease in the thickness of the endometrial stroma with reduced content of collagen fibers. There was also a reduction of 30% in pregnancy rate in the treated groups and an increase in the frequency of fetal death. This study suggests that, based on this experimental model, the insecticide may pose a reproductive risk for females chronically exposed to the substance from the pre-pubertal period until adulthood. These results raise concerns about prolonged exposure of women to the same compound.

Thyroid diseases and female sexual dysfunctions

INTRODUCTION

Female sexual dysfunctions (FSDs) have received little attention in the context of thyroid diseases, despite the high prevalence of both conditions.

OBJECTIVES

This review aims to update and summarize the state of knowledge on the association between thyroid diseases and FSDs and to investigate the complex mechanisms through which thyroid hormone imbalance can impact female sexual health in the context of the biopsychosocial model.

METHODS

A comprehensive literature search was performed through the PubMed, MEDLINE, and Scopus databases, using the following keywords: "female sexual function," "sexual dysfunction," "hypoactive sexual desire disorder," "thyroid disease," "thyroiditis," "hypothyroidism," and "hyperthyroidism."

RESULTS

To date, well-designed studies that describe the relationship between FSDs and thyroid disorders are lacking. However, despite the limitations on available studies, current data indicate that sexual alterations are frequently associated with thyroid diseases in women. A complex interplay of direct and indirect hormonal and nonhormonal mechanisms has been hypothesized, including hormonal changes, neurotransmitter imbalance, reduced nitric oxide release, mood disorders, and other systemic consequences of both hypothyroidism and hyperthyroidism. Thyroid hormone receptors have also been identified in the genitourinary system.

CONCLUSIONS

In a clinical setting, physicians should investigate the sexuality of patients consulting for thyroid disease. At the same time, an evaluation of thyroid function should be performed in patients presenting with FSD, especially after menopause, when the risk of thyroid diseases and FSDs increases strongly.

High prevalence of erectile dysfunction in men with hyperthyroidism: a meta-analysis

OBJECTIVE

The objective of this study was to evaluate the association between hyperthyroidism and the risk of developing erectile dysfunction (ED).

METHODS

A comprehensive search of multiple databases, including PubMed, Embase, Cochrane, and Web of Science, was conducted to identify relevant studies investigating the relationship between hyperthyroidism and ED in men. The quality of the included studies was assessed using the Newcastle‒Ottawa Quality Rating Scale, and a meta-analysis was performed using Stata 16.0 and RevMan 5.3 software.

RESULTS

A total of four papers encompassing 25,519 study subjects were included in the analysis. Among these, 6,429 individuals had hyperthyroidism, while 19,090 served as controls. The overall prevalence of ED in patients with hyperthyroidism was determined to be 31.1% (95% CI 0.06-0.56). In patients with uncomplicated hyperthyroidism, the incidence of ED was 21.9% (95% CI 0.05-0.38). The combined odds ratio (OR) for the four studies was 1.73 (OR: 1.73; 95% CI [1.46-2.04]; p < .00001).

CONCLUSION

Our findings demonstrate a higher incidence of ED in patients with hyperthyroidism. These results provide valuable information for healthcare professionals and can facilitate discussions surrounding appropriate treatment options for ED in patients with hyperthyroidism.

Review of mendelian randomization studies on age at natural menopause

Menopause marks the end of the reproductive phase of life. Based on epidemiological studies, abnormal age at natural menopause (ANM) is thought to contribute to a number of adverse outcomes, such as osteoporosis, cardiovascular disease, and cancer. However, the causality of these associations remains unclear. A powerful epidemiological method known as Mendelian randomization (MR) can be used to clarify the causality between ANM and other diseases or traits. The present review describes MR studies that included ANM as an exposure, outcome and mediator. The findings of MR analyses on ANM have revealed that higher body mass index, poor educational level, early age at menarche, early age at first live birth, early age at first sexual intercourse, and autoimmune thyroid disease appear to be involved in early ANM etiology. The etiology of late ANM appears to be influenced by higher free thyroxine 4 and methylene tetrahydrofolate reductase gene mutations. Furthermore, early ANM has been found to be causally associated with an increased risk of osteoporosis, fracture, type 2 diabetes mellitus, glycosylated hemoglobin, and the homeostasis model of insulin resistance level. In addition, late ANM has been found to be causally associated with an increased systolic blood pressure, higher risk of breast cancer, endometrial cancer, endometrioid ovarian carcinoma, lung cancer, longevity, airflow obstruction, and lower risk of Parkinson's disease. ANM is also a mediator for breast cancer caused by birth weight and childhood body size. However, due to the different instrumental variables used, some results of studies are inconsistent. Future studies with more valid genetic variants are needed for traits with discrepancies between MRs or between MR and other types of epidemiological studies.

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.

Epigenetic developmental programming and intergenerational effects of thyroid hormones

Mounting evidence is showing that altered signaling through the nuclear hormone receptor superfamily can cause abnormal, long-term epigenetic changes which translate into pathological modifications and susceptibility to disease. These effects seem to be more prominent if the exposure occurs early in life, when transcriptomic profiles are rapidly changing. At this time, the coordination of the complex coordinated processes of cell proliferation and differentiation that characterize mammalian development. Such exposures may also alter the epigenetic information of the germ line, potentially leading to developmental changes and abnormal outcomes in subsequent generations. Thyroid hormone (TH) signaling is mediated by specific nuclear receptors, which have the ability to markedly change chromatin structure and gene transcription, and can also regulate other determinants of epigenetic marks. TH exhibits pleiotropic effects in mammals, and during development, its action is regulated in a highly dynamic manner to suit the rapidly evolving needs of multiple tissues. Their molecular mechanisms of action, timely developmental regulation and broad biological effects place THs in a central position to play a role in the developmental epigenetic programming of adult pathophysiology and, through effects on the germ line, in inter- and trans-generational epigenetic phenomena. These areas of epigenetic research are in their infancy, and studies regarding THs are limited. In the context of their characteristics as epigenetic modifiers and their finely tuned developmental action, here we review some of the observations underscoring the role that altered TH action may play in the developmental programming of adult traits and in the phenotypes of subsequent generations via germ line transmission of altered epigenetic information. Considering the relatively high prevalence of thyroid disease and the ability of some environmental chemicals to disrupt TH action, the epigenetic effects of abnormal levels of TH action may be important contributors to the non-genetic etiology of human disease.

Premature Ejaculation and Endocrine Disorders: A Literature Review

Premature ejaculation (PE) is the most common male sexual dysfunction, with 30% of men experiencing PE worldwide. According to the generally accepted classification, there are two types of PE: lifetime PE and acquired PE. Various biological and psychological causes are known to be involved in the etiology of PE. However, due to the incomplete definition and etiopathogenesis of PE, there is no effective treatment. Although clinical and animal studies indicate that hormones play a role in controlling the ejaculation process, the precise endocrine mechanisms are unclear. In addition, little is known about the role of endocrine disorders in PE etiology. However, there is evidence that diabetes mellitus (DM), obesity, metabolic syndrome (MetS), thyroid gland disorders, pituitary gland disorders, and vitamin D deficiency affect the prevalence of PE. Moreover, it has been reported that the prevalence of PE decreases with treatment of these endocrine disorders. In this review, the relationship between PE and DM, MetS, obesity, vitamin D deficiency, and thyroid and pituitary gland disorders is summarized.

Hyperthyroidism as an Underlying Cause of Premature Ejaculation

INTRODUCTION

Hormonal imbalances have been associated with various sexual dysfunction disorders. In particular, the connection of hyperthyroidism has been discovered to correlate to premature ejaculation (PE) but has yet to been thoroughly elucidated. As one of the most frequently self-reported sexual dysfunctions, it is imperative for health care professionals to evaluate possible underlying conditions in regard to treatment options for individuals with PE.

OBJECTIVES

To review the literature regarding hyperthyroidism effects on sexual dysfunction, with a focus on hyperthyroidism and PE.

METHODS

A literature review of articles and clinical studies was performed to define the classification, pathophysiology, diagnostic considerations, and management of hyperthyroidism on PE. Search terms included "hyperthyroidism" and/or "premature ejaculation," "treatment of premature ejaculation," "defining premature ejaculation," and "management of premature ejaculation."

RESULTS

To improve the accuracy of diagnosing PE, there needs to be a set definition amongst the different guidelines, as using these guidelines can help determine possible underlying etiologies of PE. The correlation of hyperthyroidism and PE has been described in a limited number of studies. It has been reported that individuals with hyperthyroidism are much more likely to have PE than individuals with euthryoidism. Management of hyperthyroidism has been shown to alleviate the symptoms of PE.

CONCLUSION

Further understanding of hyperthyroidism as an underlying cause of PE could lead to increased efficacy of treatment and management of PE. Tannenbaum J, Youssef M, Attia AS, et al. Hyperthyroidism as an Underlying Cause of Premature Ejaculation. Sex Med Rev 2021;XX:XXX-XXX.

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.

Safety and Effectiveness of Dapoxetine On Demand in Chinese Men With Premature Ejaculation: Results of a Multicenter, Prospective, Open-Label Phase IV Study

INTRODUCTION

Dapoxetine on demand has been approved for premature ejaculation (PE) management in China; however, studies on the efficacy and safety of this treatment in the Chinese population are scarce.

AIM

The aim of this study was to evaluate the safety and effectiveness of dapoxetine 30 mg and 60 mg on demand in Chinese men with PE.

METHODS

Phase IV real-world study on 1,252 patients with PE. If men reported no response to dapoxetine 30 mg after 4 weeks treatment, dapoxetine has been uptitrated at 60 mg for 4 weeks more.

MAIN OUTCOME MEASURE

Self-reported data were collected for demographics, general and sexual health characteristics, PE severity, and treatment safety and effectiveness, as measured by the PE profile questionnaire.

RESULTS

Adverse events (AEs), such as nausea, thirst, headache, and dizziness, similarly to previous literature, were detected. The treatment-emergent AEs rate was higher in the patients treated with 30 and 60 mg (n = 192) compared with those treated with the dapoxetine 30 mg only (n = 1060) (34.4% vs 15.8%, respectively). No new safety concerns were observed. The overall effectiveness rates were 88.2% in subjects using 30 mg of dapoxetine, whereas a rescue from the previous failure was in 55.7% in the patients who received 60 mg after the initial 30 mg. Overall, 83.2% responded to dapoxetine at dosages equal to or lower than 60 mg.

CONCLUSION

The results in this study demonstrated in a large Chinese population that on-demand dapoxetine is a safe and effective symptomatic treatment in patients with PE. J Peng, L Yang, L Liu, et al. Safety and Effectiveness of Dapoxetine On Demand in Chinese Men With Premature Ejaculation: Results of a Multicenter, Prospective, Open-Label Phase IV Study. Sex Med 2021;9:100296.

Melatonin alleviates the deterioration of oocytes and hormonal disorders from mice subjected to glyphosate

Glyphosate (Gly) is the herbicide widely used in agricultural fields and landscaping. Mammalian exposure to glyphosate could cause neurotoxicity, blood, liver, kidney, endocrine, reproductive, genetic and other toxic effects. Melatonin (MT) is a neuroendocrine hormone secreted mainly by the pineal gland. It is unknown whether MT can improve reproductive defects and hormonal disorders in mice exposed to Gly. In this study, mice were exposed to 250 and 500 mg/kg Gly by intragastric administered and 15 mg/kg MT was treated via intraperitoneal injection for 7 days. Our results shown that the weight gain of mice, the ovarian coefficient and the ATP content in the ovaries were decreased significantly. Gly-treated oocytes showed that the first polar body extrusion failed, the level of oxidative stress increased, and the mitochondrial membrane potential (MMP) decreased. Subsequently, our results showed that increased expression level of BAX protein, reduced expression of BCL-2 protein, ATG12 and LC3 protein expression increased in ovaries after Gly treatment. At the same time, Gly exposure led to abnormal expression of Hypothalamic-Pituitary-Thyroid (HPT) axis-related genes and disrupted hormone homeostasis. After the injection of 15 mg/kg MT, the oocytes showed decreased oxidative stress level, increased mitochondrial membrane potential, incremental ATP content in the ovaries and the hormone levels were approached to the control group. Thus, our results demonstrated that melatonin can improve oocyte quality and maintain hormone homeostasis in mice exposed to glyphosate.

The endocrinology of sarcopenia and frailty

Sarcopenia describes low muscle mass and strength associated with ageing, whilst reduced physical performance indicates the severity of the condition. It can happen independently of other medical conditions and can be a key feature of the frailty phenotype. Frailty is a syndrome of increased vulnerability to incomplete resolution of homeostasis, following a stressor event. Researchers have described the implications of hypothalamic pituitary dysregulation in the pathogenesis of both entities. This review summarizes the recent evidence in this area as well as other endocrine factors such as insulin resistance and vitamin D status and outlines current research priorities. We conducted searches to PubMed and Embase databases for articles, reviews and studies reporting new data on the interaction between hormones of the endocrine system and frailty and/ or sarcopenia in the last 5 years. Interventional studies, cohort studies, case-control studies and animal studies were included. Clinical trials register was also searched to identify ongoing relevant studies. Studies have given us insights into the complex relationships between factors such as anabolic hormones, glucocorticoids and vitamin D on muscle strength and performance and their involvement in ageing phenotypes. However, robust randomized controlled trials are needed to consolidate existing evidence in humans and inform clinical practice. Current evidence supports hormone replacement in patients with confirmed deficiencies, to optimize health and prevent complications. Hormone replacement has limited use for age-related conditions. Current interest is focused on muscle/bone/fat interactions and health outcomes in "sarcopenic obesity." A life-course approach to improving 'health-span' is advocated. Lifestyle factors such as nutrition and physical activity have important interactions with body composition, physical function and metabolic outcomes. Large-scale clinical trials will determine the efficacy and long-term safety of hormone supplementation in the management of sarcopenia and frailty.

Sexual dream and family relationships in frequent sexual dreamers and healthy volunteers

Early life family relationships affect the sexuality in adulthood, and these influences might be reflected in sexual dreams. The present study was designed to investigate the exact associations between family relationships and sexual dream experience. We therefore invited 62 frequent sexual dreamers (dreamers) and 104 healthy volunteers (controls) to answer the Sexual Dream Experience Questionnaire (SDEQ) and the Family Relationship Questionnaire (FRQ). Compared to controls, dreamers scored higher on all SDEQ factors and sexual dream frequency, higher on FRQ Paternal Abuse, and lower on FRQ General Attachment and Maternal Freedom Release. In controls, Paternal Abuse was associated with Joyfulness, Maternal Dominance with Aversion, and Maternal Abuse with dream frequency (-). In dreamers, Paternal Abuse was associated with Aversion, Bizarreness and dream frequency, and Maternal Freedom Release with Aversion (-). In conclusion, there were pronounced associations between sexual dreams and family relationships in frequent sexual dreamers. Paternal Abuse in particular was associated with sexual dream experience. Adverse family relationships might induce frequent sexual dream occurrence, and family therapy or early intervention of Paternal Abuse might alleviate the negative sexual dream experience.

Association Between Overt Hyperthyroidism and Risk of Sexual Dysfunction in Both Sexes: A Systematic Review and Meta-Analysis

BACKGROUND

Numerous studies have shown the detrimental effects of overt hyperthyroidism on sexual functioning but a quantitative result has not yet been synthesized.

AIM

To conduct a systematic review and meta-analysis that quantifies the association between overt hyperthyroidism and the risk of sexual dysfunction (SD).

METHODS

A meta-analysis of studies in the literature published prior to February 1, 2020, from 4 electronic databases (MEDLINE, Embase, Cochrane Library databases, and PsychINFO) was conducted. All analyses were performed using the random-effects model comparing individuals with and without overt hyperthyroidism.

OUTCOMES

The strength of the association between overt hyperthyroidism and risk of SD was quantified by calculating the relative risk (RR) and the standard mean difierences with 95% CI. The quality of evidence for the reported outcome was based on the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Of 571 publications, a total of 7 studies involving 323,257 individuals were included. Synthetic results from 7 eligible studies indicated that overt hyperthyroidism led to significant SD in both sexes (pooled RR = 2.59, 95% CI: 1.3-5.17, P = .007; heterogeneity: I² = 98.8%, P < .001). When we analyzed the data of men and women independently, the pooled results consistently showed that men and women with overt hyperthyroidism were at over 2-fold higher risk of SD than the general populations (RR for males = 2.59, 95% CI: 1.03-6.52, P = .044; RR for females = 2.51, 95% CI: 1.47-4.28, P = .001). Combined standard mean diffierences from those studies providing the Female Sexual Function Index (FSFI) suggested that women with overt hyperthyroidism were associated with a significantly lower FSFI value in FSFI total scores, subscale sexual arousal, lubrication, orgasm, and satisfaction domain (all P < .05). The overall quality of evidence in our study was considered to be moderate.

CLINICAL IMPLICATIONS

Clinicians should know the detrimental effects of overt hyperthyroidism on sexual functioning in clinical practice. Measurement of thyroid hormones should be included in the assessment of patients presenting with SD when they show symptoms of clinical hyperthyroidism.

STRENGTHS & LIMITATIONS

This is the first meta-analysis quantifying the relationship between overt hyperthyroidism and the risks of SD. However, the combined results were derived from limited retrospective studies along with substantial heterogeneities.

CONCLUSION

Our study has confirmed the potentially devastating sexual health consequences caused by overt hyperthyroidism. However, additional rigorous studies with sizable samples are still needed to better elucidate this evidence. Pan Y, Xie Q, Zhang Z, et al. Association Between Overt Hyperthyroidism and Risk of Sexual Dysfunction in Both Sexes: A Systematic Review and Meta-Analysis. J Sex Med 2020;17:2198-2207.

Identification and characterization of male reproduction-related genes in pig (Sus scrofa) using transcriptome analysis

BACKGROUND

The systematic interrogation of reproduction-related genes was key to gain a comprehensive understanding of the molecular mechanisms underlying male reproductive traits in mammals. Here, based on the data collected from the NCBI SRA database, this study first revealed the genes involved in porcine male reproduction as well their uncharacterized transcriptional characteristics.

RESULTS

Results showed that the transcription of porcine genome was more widespread in testis than in other organs (the same for other mammals) and that testis had more tissue-specific genes (1210) than other organs. GO and GSEA analyses suggested that the identified test is-specific genes (TSGs) were associated with male reproduction. Subsequently, the transcriptional characteristics of porcine TSGs, which were conserved across different mammals, were uncovered. Data showed that 195 porcine TSGs shared similar expression patterns with other mammals (cattle, sheep, human and mouse), and had relatively higher transcription abundances and tissue specificity than low-conserved TSGs. Additionally, further analysis of the results suggested that alternative splicing, transcription factors binding, and the presence of other functionally similar genes were all involved in the regulation of porcine TSGs transcription.

CONCLUSIONS

Overall, this analysis revealed an extensive gene set involved in the regulation of porcine male reproduction and their dynamic transcription patterns. Data reported here provide valuable insights for a further improvement of the economic benefits of pigs as well as future treatments for male infertility.

The subtle balance of insulin and thyroxine on survival and development of in vitro cultured caprine preantral follicles enclosed in ovarian tissue

Numerous studies have reported the importance of thyroid hormones on the development of later preantral and antral follicles, but their interactions with other hormones and effects in regulating early preantral follicle growth remain unclear. Here we investigated the in vitro effects of thyroxine combined with insulin on caprine preantral follicle survival and development. Sliced ovarian tissues were cultured for 1 or 7 days using 10 ng/mL (low) or 10 μg/mL (high) insulin in the presence of thyroxine at 0, 0.5, 1 or 2 μg/mL. Post-culture, we evaluated the follicular survival and development, assessed the expression of apoptotic-related genes (Bcl2/Bax) and receptors of insulin and thyroid hormones, and quantified the estradiol and reactive oxygen species (ROS) production levels. Follicular survival in low-insulin culture conditions was enhanced by the presence of 0.5 μg/mL thyroxine (P < 0.05) as compared to the thyroxine-free medium but remained similar to non-cultured control in the presence of 2 μg/mL (P > 0.05). Significantly higher ROS production was measured from Day 1 to Day 7 in low-insulin culture media containing 0.5 or 2 μg/mL thyroxine (P < 0.05). When compared to high insulin level, the presence of thyroxine in low insulin culture conditions yielded higher stromal cell density (P < 0.05), increased estradiol production on Day 1, and higher Bcl2/Bax ratio on Day 7. Cultures with high levels of both insulin and thyroxine led to follicles and oocytes with larger diameters (P < 0.05). The RNA transcript levels of insulin and thyroid receptors were reduced in the presence of high insulin cultures when compared to controls (non-cultured). In conclusion, the combination of low concentrations of insulin and thyroxine better maintained follicle survival, while high levels ensured better follicular development.

Effects of Hypothyroidism and Subclinical Hypothyroidism on Sexual Function: A Meta-Analysis of Studies Using the Female Sexual Function Index

Introduction

Hypothyroidism and subclinical hypothyroidism (SCH) are common metabolic diseases with severe psychological and physiological effects, which may be the risk factors of sexual dysfunction.

Aim

The purpose of this study is to explore the influence of hypothyroidism and SCH on female sexual function through systematic literature review.

Methods

Until February 2020, systematic searches were conducted on Pubmed, Web of Science, EMBASE, and Clinicalkey to obtain eligible studies to report the mean and standard deviation of Female Sexual Function Index (FSFI) in various fields in women with clinical hypothyroidism, SCH, and healthy controls. In accordance with the results of heterogeneity test, a random effect model or fixed effect model was selected to aggregate the scores of each field. The scores of female patients with hypothyroidism and healthy controls were compared using forest plot. Stata (version 15.1) uses meta-analysis.

Main Outcome Measure

Evaluation values of various fields of FSFI in clinical hypothyroidism, SCH, and healthy controls.

Results

This study included 7 studies, including 88 women with clinical hypothyroidism, 337 women with SCH, and 2056 healthy controls. Compared with healthy controls, patients with hypothyroidism scored lower in all FSFI dimensions (desire, arousal, lubrication, orgasm, satisfaction, and pain), especially in lubrication. And, only arousal and orgasm decreased in patients with SCH. Hypothyroidism (odds ratio = 3.912, P = .002) rather than SCH (odds ratio = 1.036, P = .886) was a risk factor for female sexual dysfunction.

Conclusion

Hypothyroidism does impair female sexual function to varying degrees. SCH has little effect on female sexual function. It is essential to measure and evaluate the thyroid function of women with sexual dysfunction regularly, which can help clinicians improve sexual function and sexual quality of life.

Wang Y and Wang H. Effects of Hypothyroidism and Subclinical Hypothyroidism on Sexual Function: A Meta-Analysis of Studies Using the Female Sexual Function Index. Sex Med 2020;8:156–167.

Thyroid function in Klinefelter syndrome: a multicentre study from KING group

PURPOSE

The prevalence and the etiopathogenesis of thyroid dysfunctions in Klinefelter syndrome (KS) are still unclear. The primary aim of this study was to evaluate the pathogenetic role of hypogonadism in the thyroid disorders described in KS, with the scope to distinguish between patients with KS and hypogonadism due to other causes (Kallmann syndrome, idiopathic hypogonadotropic hypogonadism, iatrogenic hypogonadism and acquired hypogonadotropic hypogonadism after surgical removal of pituitary adenomas) called non-KS. Therefore, we evaluated thyroid function in KS and in non-KS hypogonadal patients.

METHODS

This is a case-control multicentre study from KING group: Endocrinology clinics in university-affiliated medical centres. One hundred and seventy four KS, and sixty-two non-KS hypogonadal men were enrolled. The primary outcome was the prevalence of thyroid diseases in KS and in non-KS. Changes in hormonal parameters were evaluated. Exclusion criterion was secondary hypothyroidism. Analyses were performed using Student's t test. Mann-Whitney test and Chi-square test.

RESULTS

FT4 was significantly lower in KS vs non-KS. KS and non-KS presented similar TSH and testosterone levels. Hashimoto's thyroiditis (HT) was diagnosed in 7% of KS. Five KS developed hypothyroidism. The ratio FT3/FT4 was similar in both groups. TSH index was 1.9 in KS and 2.3 in non-KS. Adjustment for differences in age, sample size and concomitant disease in multivariate models did not alter the results.

CONCLUSIONS

We demonstrated in KS no etiopathogenic link to hypogonadism or change in the set point of thyrotrophic control in the altered FT4 production. The prevalence of HT in KS was similar to normal male population, showing absence of increased risk of HT associated with the XXY karyotype.

Gender difference and correlation between sexuality, thyroid hormones, cognitive, and physical functions in elderly fit

PURPOSE

Sexuality in the elderly is related to psycho-physical well-being. Aim of this study was to analyze the correlation between sexual health, thyroid hormones, cognitive functions, and physical fitness in elderly population.

METHODS

Fifty-one fit adults were recruited (age: 71.9 ± 5.3 years, 26 females and 25 males). Sexuality was evaluated using the Changes in Sexual Functioning Questionnaire-short form (CSFQ-14) and the Sexual Attitude Scale (SAS). Thyroid function was assessed by measuring serum TSH, FT3, and FT4. Cognitive functions and depressive symptoms were evaluated by the Mini Mental State Examination (MMSE) test and Geriatric Depression Scale (GDS) scores. Subjects' physical fitness was evaluated using the following tests: Short Physical Performance Battery (SPPB), Handgrip test (HG), Timed Up and Go test (TUG), and 2-Minute step test (ST).

RESULTS

CSFQ-14 positively correlated with MMSE (p < 0.05) and negatively with GDS (p < 0.05), while thyroid function was not correlated with sexuality, in both genders. A negative relationship between FT4 vs. weight, FT3 vs. HG and FT3/FT4 ratio vs. ST were found (p = 0.05) in females, while in males, it occurred for TSH vs. TUG (p < 0.05); a positive relationship existed in females between FT4 vs. ST (p < 0.05). Finally, CSFQ-14 was significantly correlated with SPPB (p < 0.05), CST, TUG, and ST (p < 0.01), in both genders.

CONCLUSION

We demonstrated a strict relationship between active sexuality, preserved cognitive function and appropriate physical fitness in elderly subjects, independently from gender. Our preliminary data suggest that in elderly fit population, peripheral thyroxin deiodination may be a useful predictor of better physical performance and more successful aging.

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.

Effect of Thyroid Hormone Derangements on Sexual Function in Men and Women

INTRODUCTION

Sexual dysfunction affects many people, with 33‒60% of women reporting sexual dysfunction and 8‒52% of men with erectile dysfunction or premature ejaculation. In an effort to determine the constellation of factors responsible for sexual dysfunction, the effect of thyroid hormone derangements has been of recent interest.

AIM

To investigate the associations between thyroid hormones and sexual dysfunction in women and men.

METHODS

Literature was reviewed to examine the effects of hypo- and hyperthyroidism on sexual function.

MAIN OUTCOME MEASURE

We present a summary of the effects of thyroid dysfunction on domains of sexual functioning.

RESULTS

Most studies demonstrate that men with hypo- and hyperthyroidism have increased rates of sexual dysfunction, including erectile dysfunction in men with hypothyroidism. However, studies vary on the strength of correlation between hormonal derangement and level of sexual dysfunction. In both men with hyper- and hypothyroidism, treating the thyroid disorder at least partially reverses sexual dysfunction. In contrast, the current literature provides no consensus on the effect of hypothyroidism, hyperthyroidism, or Hashimoto's thyroiditis on female sexual function. In studies that observed increased rates of sexual dysfunction in women with thyroid disorders, correction of the thyroid derangement resulted in resolution of some sexual dysfunction. Studies are also conflicted on whether there is a relationship between the degree of sexual dysfunction and the degree of hormone derangement in women. However, prior work has demonstrated a relationship between thyroid autoantibodies and sexual dysfunction in women.

CONCLUSION

Thyroid dysfunction is an important factor in the pathogenesis of sexual dysfunction in men and possibly women. Evidence suggests a reversibility of sexual dysfunction with correction of thyroid dysfunction, although the exact pathophysiology of thyroid-mediated sexual dysfunction remains unknown. However, current evidence supports thyroid derangements rather than autoantibodies as the causative factor in men, whereas autoantibodies appear to play a more prominent role in women. Bates JN, Kohn TP, Pastuszak AW. Effect of Thyroid Hormone Derangements on Sexual Function in Men and Women. Sex Med Rev 2020;8:217-230.