Androgens, obesity, and sleep-disordered breathing in men

Variations in objectively measured sleep parameters in patients with different premature ejaculation syndromes

BACKGROUND

Poor sleep quality is now a cause of sexual dysfunction.

AIM

To investigate variations in sleep quality among patients with different types of premature ejaculation (PE) and a control group.

METHODS

Patients with PE were categorized into groups according to 4 types: lifelong (LPE), acquired (APE), variable (VPE), and subjective (SPE). Basic demographic information about the participants was first collected, and then clinical data were obtained.

OUTCOMES

Outcomes included the 5-item International Index of Erectile Function, Premature Ejaculation Diagnostic Tool, 7-item Generalized Anxiety Disorder, 9-item Patient Health Questionnaire, Pittsburgh Sleep Quality Index, self-estimated intravaginal ejaculation latency time (minutes), and sleep monitoring parameters obtained from a wearable device (Fitbit Charge 2).

RESULTS

A total of 215 participants were enrolled in the study, of which 136 patients with PE were distributed as follows: LPE (31.62%), APE (42.65%), VPE (10.29%), and SPE (15.44%). Subjective scales showed that patients with APE were accompanied by a higher prevalence of erectile dysfunction, anxiety, and depression, as well as poorer sleep quality (assessed by the Pittsburgh Sleep Quality Index). The results of objective sleep parameters revealed that average durations of sleep onset latency (minutes) and wake after sleep onset (minutes) in patients with APE (mean ± SD; 20.03 ± 9.14, 55 ± 23.15) were significantly higher than those with LPE (15.07 ± 5.19, 45.09 ± 20.14), VPE (13.64 ± 3.73, 38.14 ± 11.53), and SPE (14.81 ± 4.33, 42.86 ± 13.14) and the control group (12.48 ± 3.45, 37.14 ± 15.01; P < .05). The average duration of rapid eye movement (REM; minutes) in patients with APE (71.34 ± 23.18) was significantly lower than that in patients with LPE (79.67 ± 21.53), VPE (85.93 ± 6.93), and SPE (80.86 ± 13.04) and the control group (86.56 ± 11.93; P < .05). Similarly, when compared with the control group, patients with LPE had significantly longer durations of sleep onset latency and wake after sleep onset and a significantly shorter duration of REM sleep.

CLINICAL IMPLICATIONS

Our study suggests that clinicians should pay attention not only to male physical assessment but also to mental health and sleep quality.

STRENGTHS AND LIMITATIONS

This study suggests that changes in sleep structure occur in patients with PE, which may provide some direction for future research. However, the cross-sectional study design does not allow us to conclude that sleep is a risk factor for PE.

CONCLUSION

After controlling for traditional parameters such as age, erectile dysfunction, anxiety, and depression, sleep parameters are independently associated with PE. Patients with APE and LPE show significant alterations in sleep parameters, with patients with APE having notably poorer sleep quality, whereas patients with VPE and SPE have sleep parameters similar to controls.

Urinary Epinephrine Sulfate Can Predict Cardiovascular Risk in Moderate-to-Severe OSA: A Metabolomics-Based Study

Purpose

There are currently no ideal indicators for predicting the cardiovascular risk of obstructive sleep apnea (OSA). This study aimed to employ urinary metabolomics to detect early cardiovascular risk in patients with moderate-to-severe OSA.

Patients and Methods

Male participants who underwent polysomnography from November 2020 to May 2021 were screened. Clinical data, polysomnography data and urine samples were collected. Untargeted metabolomics analyses of urine were performed. Multivariate analyses and receiver operating characteristic (ROC) curve analyses were subsequently performed to identify potential biomarkers. Associations between metabolites and clinical indicators and cardiovascular risk were examined through linear regression analyses with interaction and mediation analyses.

Results

Thirty-six male participants were included in the study, comprising 22 males with moderate-to-severe OSA and 14 age-matched controls, with an average age of 39.6 ± 9.2 years. We identified 65 metabolites in the study, involving pathways including pyrimidine, androgen, estrogen, vitamin B6 and sulfate/sulfite metabolism. Among them, epinephrine sulfate was the most significantly altered metabolite. ROC analyses highlighted that epinephrine sulfate had the highest area under the curve (AUC=0.883) for detecting moderate-to-severe OSA. Epinephrine sulfate was statistically correlated with OSA severity, hypoxia-related indicators (apnea-hypopnea index: r=0.685; oxygen desaturation index: r=0.743, p<0.0001), arterial stiffness (arterial augmentation index: r=0.361, p=0.031) and long-term cardiovascular risk (Framingham cardiovascular risk: r=0.375, p=0.024). Linear regression analysis revealed that epinephrine sulfate was significantly associated with an increased in the Framingham risk (β = 0.004, 95% CI = 0.000-0.009, p = 0.049), with the effect partly mediated by systolic blood pressure (27.6%) and not moderated by other factors. Additionally, it also significantly associated with the increased in the arterial augmentation index (β = 0.019, 95% CI = 0.000-0.037, p = 0.046), with the effect fully mediated by blood pressure and not moderated by other indices statistically.

Conclusion

There are significant metabolic pathway alterations in moderate-to-severe OSA patients. Urinary epinephrine sulfate markedly predicts early cardiovascular risk in OSA patients.

Sleep, testosterone and cortisol balance, and ageing men

Sleep serves important biological functions, and influences health and longevity through endocrine and metabolic related systems. Sleep debt, circadian misalignment and sleep disruption from obstructive sleep apnea is widespread in modern society and accumulates with life because recovery sleep is not completely restorative. Accumulated disordered sleep throughout life impacts the ageing process and the development of age-related diseases. When epidemiological and interventional studies are considered collectively, sleep loss and lower sleep duration are associated with lower morning, afternoon and 24-h testosterone; as well as higher afternoon, but not morning or 24-h cortisol. These reciprocal changes imbalances anabolic-catabolic signaling because testosterone and cortisol are respectively the main anabolic and catabolic signals in man. Fixing testosterone-cortisol balance by means of a novel dual-hormone clamp mitigates the induction of insulin resistance by sleep restriction and provided the first proof-of-concept that the metabolic harm from sleep loss can be ameliorated by approaches that do not require sleeping more. Obstructive sleep apnea is associated with lower testosterone, even after controlling for age and obesity whereas the conclusion that continuous positive airway pressure therapy has no effect on testosterone is premature because available studies are underpowered and better-quality studies suggest otherwise. High dose testosterone therapy induces OSA, but more physiological dosing may not; and this effect may be transient or may dissipate with longer term therapy. Studies investigating the origin of the diurnal testosterone rhythm, the effect of circadian misalignment on testosterone-cortisol balance, and methods to mitigate metabolic harm, are required.

Variation in the sexual behavior and blood count parameters induced by sleep deprivation in male rats

BACKGROUND

Sleep is a fundamental biological requirement, and lack of sleep has increasingly been recognized to cause metabolic consequences and adversely affect immune function. Recent articles have pointed to how sleep and sexual functions may be interlinked, involving inflammation, vascular alterations, tissue damage, and endothelial dysfunction.

OBJECTIVES

We examined the effect of paradoxical sleep deprivation (PSD) on sexual behavior and hemogram parameters in male rats. In addition, we also explored whether 7 days of recovery sleep is sufficient to offset these detriments.

MATERIALS AND METHODS

 Male rats were given sexual experience through training. At the 5th test, the sexually vigorous males were randomly separated into 3 experimental groups: PSD (rats submitted to 96 hours of PSD, n = 6), RS (recovery sleep 7 days after PSD, n = 6), and control (n = 10). We evaluated the sexual behaviors of three groups. Blood samples were collected to analysis hemogram parameters.

RESULTS

In this study, we recognized that repeated copulatory tests can lead to changes in sexual behavior over time. We found that 96 hours of acute sleep deprivation impaired the sexual behavior of male rats. Our results demonstrated that 96 hours of PSD also increased levels of white blood cell (WBC) subpopulations, in particular neutrophils. Recovery sleep after sleep deprivation has a certain reversal effect on WBC subgroups and impairment of sexual behavior, with some signs that not all levels were back to baseline even after 7 days of recovery.

CONCLUSION

In general, we found that 96 hours of PSD impaired the sexual behavior of male rats. Our results demonstrated that PSD can cause systemic inflammation by affecting WBC subpopulations, in particular neutrophils. 7 days of recovery sleep after sleep deprivation has a certain reversal effect to these impairments. This article is protected by copyright. All rights reserved.

Proteomic analysis reveals proteins and pathways associated with declined testosterone production in male obese mice after chronic high-altitude exposure

OBJECTIVE

Obesity is common in highland areas owing to lifestyle alterations. There are pieces of evidence to suggest that both obesity and hypoxia may promote oxidative stress, leading to hypogonadism in males. These findings indicate an increased risk of hypogonadism in obese males following hypoxia exposure. However, the mechanisms underlying the disease process remain unclear. The current study aims to explore the mechanism of testosterone production dysfunction in obese male mice exposed to a chronic high-altitude hypoxia environment.

METHODS

An obese male mouse model was generated by inducing obesity in mice via a high-fat diet for 14 weeks, and the obese mice were then exposed to a high-altitude hypoxia environment for 24 days. Sera and testicular tissues were collected to detect serum lipids, sex hormone level, and testicular oxidative stress indicators. Morphological examination was performed to assess pathological alterations in testicular tissues and suborganelles in leydig cells. Proteomic alterations in testicular tissues were investigated using quantitative proteomics in Obese/Control and Obese-Hypoxia/Obese groups.

RESULTS

The results showed that chronic high-altitude hypoxia exposure aggravated low testosterone production in obese male mice accompanied by increased testicular oxidative stress and histological damages. In total, 363 and 242 differentially expressed proteins (DEPs) were identified in the two comparison groups, Obese/Control and Obese-Hypoxia/Obese, respectively. Functional enrichment analysis demonstrated that several significant functional terms and pathways related to testosterone production were altered in the two comparison groups. These included cholesterol metabolism, steroid hormone biosynthesis, peroxisome proliferator-activated receptor (PPAR) signaling pathway, oxidative stress responses, as well as retinol metabolism. Finally, 10 representative DEPs were selected for parallel reaction monitoring verification. Among them, StAR, DHCR7, NSDHL, CYP51A1, FDPS, FDX1, CYP11A1, ALDH1A1, and GPX3 were confirmed to be downregulated in the two groups.

CONCLUSIONS

Chronic hypoxia exposure could exacerbate low testosterone production in obese male mice by influencing the expression of key proteins involved in steroid hormone biosynthesis, cholesterol biosynthesis, oxidative stress responses and retinol metabolism.

Poor Sleep Quality is an Independent Risk Factor for Acquired Premature Ejaculation

PURPOSE

To determine the role of poor sleep quality as a risk factor for acquired premature ejaculation (APE) after considering the various risk factors, such as ages, lower urinary tract symptoms (LUTS), anxiety, depression, and erectile dysfunction.

METHODS

This study presents a multivariate analysis to identify risk factors for PE, including the covariate of age, International Prostate Symptom Score (IPSS), General Anxiety Disorder-7 (GAD-7) score, Patient Health Questionnaire-9 (PHQ-9) score, International Index of Erectile Function (IIEF) score, and Pittsburgh Sleep Quality Index (PSQI). Acquired PE was defined as self-reported intravaginal ejaculation latency time ≤3 minutes, and poor sleep quality was diagnosed using the Pittsburgh Sleep Quality Index tool.

RESULTS

A total of 349 men were enrolled in the study after completing the questionnaires and the medical history survey. Among 349 men, 203 individuals (58.17%) suffered from acquired PE. The IIEF-5 score, IPSS, GAD-7 score, PHQ-9 score, and PSQI score of the population with PE were significantly different from the non-PE group. Further multivariate analysis showed that erectile dysfunction, depression, severe prostatitis-like symptoms, and poor sleep quality were high-risk factors of APE. Additionally, our study showed that premature ejaculation diagnostic tool (PEDT) score was associated with IPSS/GAD-7/PHQ-9/PSQI scores positively and associated with IIEF-5 scores negatively. The stratified analysis of sleep quality showed that APE patients with different sleep qualities have different prevalence rates of anxiety, depression, prostatitis-like symptoms, and erectile function.

CONCLUSION

In general, sleep quality may be a potential risk factor for patients with acquired premature ejaculation. Our research revealed the impact of sleep quality on premature ejaculation and provided new viewpoints for further understanding and perfecting the pathogenesis of premature ejaculation.

Sleep and the Testis

Disordered sleep impairs neurocognitive performance, and is now recognized to cause metabolic ill-health. This review assesses the nascent relationship between insufficient, misaligned, and disrupted sleep with andrological health. High-quality cohort studies show a reduced sperm count in men with sleep disturbances. Well-designed interventional studies show a reduction in testosterone with sleep restriction. Studies of long-term shift workers show no effect of misaligned sleep on mean testosterone concentrations. Men with obstructive sleep apnea (OSA) and more severe hypoxemia have lower testosterone levels, although it is unknown if this relationship is entirely explained by concomitant obesity, or is reversible. Nevertheless, erectile dysfunction, which is common in men with OSA, is clinically improved when OSA is properly treated. Few studies manipulating sleep have been performed in older men, in whom the accumulation of sleep disturbances over decades of life may contribute to age-related illnesses. Improving sleep could ameliorate the development of these disorders.

A Clinical Perspective of Sleep and Andrological Health: Assessment, Treatment Considerations, and Future Research

CONTEXT

Sleep that is insufficient, misaligned, or disrupted causes hypersomnolence and neuropsychological deficits, adversely affects cardiometabolic health, and is increasingly recognized to impair other biological processes that lead to conditions important to men, such as hypogonadism, erectile dysfunction, and infertility.

EVIDENCE ACQUISITION

Literature review from 1970 to December 2018.

EVIDENCE SYNTHESIS

High-quality and complementary epidemiological and interventional studies establish that abnormal sleep is associated with increased mortality, hypertension, and other cardiometabolic disorders (insufficient, disrupted, and misaligned sleep), as well as reduced fecundity and total sperm count (insufficient sleep), erectile dysfunction (disrupted sleep), and low testosterone (both). Circadian misalignment shifts the peak of testosterone's diurnal rhythm to occur soon after waking up, irrespective of the biological clock time, but it does not change the mean concentration. Preliminary studies show that extending sleep in individuals who are chronically sleep deprived may become a strategy to reduce insulin resistance and hypertension. Continuous positive airway pressure therapy can improve erectile function, and possibly systemic testosterone exposure, but only when used adherently by men with obstructive sleep apnea. Both high-dose and replacement-dose testosterone therapies modestly worsen sleep-disordered breathing, but they also improve cardiometabolic function and sexual desire. Persistence of either the adverse or beneficial outcomes over the longer term requires further investigation.

CONCLUSIONS

Sleep is increasingly recognized to be essential for healthy living. Establishing the effect of abnormal sleep, and of improving sleep, on andrological issues of prime interest to men will promote prioritization of sleep, and may thereby improve overall long-term health outcomes.

Transcription regulation of NRF1 on StAR reduces testosterone synthesis in hypoxemic murine

Male chronic obstructive pulmonary disease (COPD) and sleep apnea patients are associated with serum testosterone level decline because of hypoxemia, resulting in male sexual dysfunction and lower reproductive capacity. Although testosterone replacement therapy used in clinic achieves good results, the side effects indicates that understanding the mechanism followed with targeted treatments are more meaningful. The known mechanism of Hypoxia-inducible factor-1 (HIF-1) mediated steroidogenic acute regulatory protein (StAR) repression did not well explain the reason of hypoxia induced testosterone decline. Our primary results indicated Nuclear respiratory factor 1(NRF1) might be participate in StAR transcription regulation. The study aims to identify the mechanism of the regulation of StAR by NRF1, providing an explanation for the decrease of testosterone induced by hypoxemia. Testosterone level and StAR were determined in COPD model rats, sleep apnea model mice and hypoxia rats (10%O₂). Results indicated NRF1, StAR and testosterone decreased in testis and ovary and increased in adrenal. Regulation of NRF1 expression under normoxia or hypoxia induced synchronous changes of both StAR and testosterone, indicating the decrease of NRF1 induced StAR repression in hypoxemia were the main cause of serum testosterone decline. The results were confirmed by dual-luciferase reporter assays, regulation of NRF1 synchronously altered the transcriptional activity of StAR. By ChIP, EMSA supershift, NRF1 was found to bind to the Star promoter region. Mutation assays identified two NRF1-binding sites on mouse Star promoter. These findings indicated that NRF1 positivly regulated Star transcription through directly binding to the Star promoter at -1445/-1422 and -44/-19.

Varicoceles: prevalence and pathogenesis in adult men

Varicocele, or dilation of the pampiniform venous plexus, affects up to 15% of men. However, few of these men encounter problems with fertility. This discrepancy between men with varicocele and the number of adversely affected men has led to abundant research to identify the mechanisms for formation of varicocele as well as the pathologic mechanisms by which varicoceles affect fertility potential. In this review, we discuss the prevalence of varicocele in adults, the anatomic features of varicocele, the leading theories as to how varicocele can negatively affect fertility potential, and finally, the current literature on the impact of varicocele on testosterone production.

Endocrine targets of hypoxia-inducible factors

Endocrine is an important and tightly regulated system for maintaining body homeostasis. Endocrine glands produce hormones, which are released into blood stream to guide the target cells responding to all sorts of stimulations. For maintaining body homeostasis, the secretion and activity of a particular hormone needs to be adjusted in responding to environmental challenges such as changes in nutritional status or chronic stress. Hypoxia, a status caused by reduced oxygen availability or imbalance of oxygen consumption/supply in an organ or within a cell, is a stress that affects many physiological and pathological processes. Hypoxic stress in endocrine organs is especially critical because endocrine glands control body homeostasis. Local hypoxia affects not only the particular gland but also the downstream cells/organs regulated by hormones secreted from this gland. Hypoxia-inducible factors (HIFs) are transcription factors that function as master regulators of oxygen homeostasis. Recent studies report that aberrant expression of HIFs in endocrine organs may result in the development and/or progression of diseases including diabetes, endometriosis, infertility and cancers. In this article, we will review recent findings in HIF-mediated endocrine organ dysfunction and the systemic syndromes caused by these disorders.

Increased sexual desire with exogenous testosterone administration in men with obstructive sleep apnea: a randomized placebo-controlled study

Testosterone (T) deficiency, sexual dysfunction, obesity and obstructive sleep apnea (OSA) are common and often coexist. T prescriptions have increased worldwide during the last decade, including to those with undiagnosed or untreated OSA. The effect of T administration on sexual function, neurocognitive performance and quality of life in these men is poorly defined. The aim of this study was to examine the impact of T administration on sexual function, quality of life and neurocognitive performance in obese men with OSA. We also secondarily examined whether baseline T might modify the effects of T treatment by dichotomizing on baseline T levels pre-specified at 8, 11 and 13 nmol/L. This was a randomized placebo-controlled study in which 67 obese men with OSA (mean age 49 ± 1.3 years) were randomized to receive intramuscular injections of either 1000 mg T undecanoate or placebo at baseline, week 6 and week 12. All participants were concurrently enrolled in a weight loss program. General and sleep-related quality of life, neurocognitive performance and subjective sexual function were assessed before and 6, 12 and 18 weeks after therapy. T compared to placebo increased sexual desire (p = 0.004) in all men, irrespective of baseline T levels. There were no differences in erectile function, frequency of sexual attempts, orgasmic ability, general or sleep-related quality of life or neurocognitive function (all p = NS). In those with baseline T levels below 8 nmol/L, T increased vitality (p = 0.004), and reduced reports of feeling down (p = 0.002) and nervousness (p = 0.03). Our findings show that 18 weeks of T therapy increased sexual desire in obese men with OSA independently of baseline T levels whereas improvements in quality of life were evident only in those with T levels below 8 nmol/L. These small improvements would need to be balanced against potentially more serious adverse effects of T therapy on breathing.

The putative mechanisms underlying testosterone and cardiovascular risk

The use of testosterone supplementation therapy (TST) is increasing primarily in men with symptomatic hypogonadism. While TST has been shown to have numerous benefits, as its use increases, the role on cardiovascular health must be explored. Previous evidence showed no adverse cardiovascular risks associated with TST use; however, more recent studies suggest that there may be an associated risk. The exact mechanism by which TST may contribute to cardiovascular risk has not been elucidated. Numerous mechanisms have been proposed which include testosterone's effect on thromboxane A2 receptors, vascular adhesion molecule 1 receptors, erythropoiesis, and obstructive sleep apnea, all of which can ultimately lead to atherogenesis and increased cardiovascular risk.

The putative mechanisms underlying testosterone and cardiovascular risk

The use of testosterone supplementation therapy (TST) is increasing primarily in men with symptomatic hypogonadism. While TST has been shown to have numerous benefits, as its use increases, the role on cardiovascular health must be explored. Previous evidence showed no adverse cardiovascular risks associated with TST use; however, more recent studies suggest that there may be an associated risk. The exact mechanism by which TST may contribute to cardiovascular risk has not been elucidated. Numerous mechanisms have been proposed which include testosterone's effect on thromboxane A2 receptors, vascular adhesion molecule 1 receptors, erythropoiesis, and obstructive sleep apnea, all of which can ultimately lead to atherogenesis and increased cardiovascular risk.

Body compositional and cardiometabolic effects of testosterone therapy in obese men with severe obstructive sleep apnoea: a randomised placebo-controlled trial

BACKGROUND

The combination of male gender, obstructive sleep apnoea (OSA) and obesity magnifies cardiometabolic risk. There has been no systematic study evaluating whether testosterone therapy can improve cardiometabolic health in obese men with OSA by improving body composition, visceral abdominal fat and insulin sensitivity.

OBJECTIVE

To assess body compositional and cardiometabolic effects of testosterone treatment in obese men with severe OSA.

DESIGN

An 18-week randomised, double-blind, placebo-controlled and parallel group trial in 67 men.

METHODS

Participants (age=49 ± 12 years, apnoea hypopnoea index=39.9 ± 17.7 events/h, BMI=31.3 ± 5.2 kg/m(2)) were placed on a hypocaloric diet and received i.m. injections of either 1000 mg testosterone undecanoate (n=33) or placebo (n=34) for 18 weeks. Outcomes were the changes in body composition (total muscle mass, total and abdominal fat, total body dual-energy X-ray absorptiometry and computerised tomography (CT)), weight, insulin sensitivity (homeostasis model assessment), abdominal liver fat (CT), arterial stiffness (pulse wave analysis), resting metabolic rate and respiratory quotient (indirect calorimetry) and blood lipids and metabolic syndrome from baseline to week 18.

RESULTS

After 18 weeks, testosterone treatment increased insulin sensitivity (-1.14 units, 95% confidence interval (95% CI) -2.27 to -0.01, P<0.05), reduced liver fat (0.09 Hounsfield attenuation ratio, 95% CI 0.009 to 0.17, P=0.03) and increased muscle mass (1.6 kg, 95% CI 0.69 to 2.5, P=0.0009) to a greater extent than placebo. Other measures of body composition and regional adiposity as well as the number of participants with metabolic syndrome did not change. Testosterone also decreased arterial stiffness (augmentation index) by 3.2% (95% CI -6.01 to -0.46%, P=0.02) and decreased the respiratory quotient (95% CI -0.04, -0.08 to -0.001, P=0.04) after 18 weeks compared with placebo.

CONCLUSION

Eighteen weeks of testosterone therapy in obese men with OSA improved several important cardiometabolic parameters but did not differentially reduce overall weight or the metabolic syndrome. Longer term studies are required.

Effects of testosterone therapy on sleep and breathing in obese men with severe obstructive sleep apnoea: a randomized placebo-controlled trial

STUDY OBJECTIVES

High doses of short-term testosterone have been shown to acutely worsen sleep-disordered breathing in men with obstructive sleep apnoea (OSA). The effects of lower, near-conventional doses of testosterone in obese men with OSA may differ over the longer term but have not been systematically studied. We assessed sleep and breathing effects of near-conventional testosterone treatment as an adjunct to weight loss in obese men with severe OSA.

DESIGN

An 18-week randomized, double-blind, placebo-controlled, parallel group trial in 67 men.

INTERVENTIONS

All subjects were placed on a hypocaloric diet and then received intramuscular injections of 1000 mg testosterone undecanoate or placebo at 0, 6 and 12 weeks.

MEASUREMENTS AND RESULTS

Sleep and breathing were measured by nocturnal polysomnography at 0, 7 and 18 weeks. Testosterone, compared to placebo, worsened the oxygen desaturation index (ODI) by 10·3 events/h (95%CI, 0·8-19·8 events/h; P = 0·03) and nocturnal hypoxaemia (sleep time with oxygen saturation <90%, SpO(2) T90%) by 6·1% (95%CI, 1·5-10·6; P = 0·01) at 7 weeks. Testosterone therapy did not alter ODI (4·5, -5·4 to 14·4 events/h; P = 0·36) or SpO(2) T90% at 18 weeks (2·9, -1·9-7·7%; P = 0·23) compared to placebo. The testosterone treatment effects on ODI and SpO(2) T90% were not influenced by baseline testosterone concentrations (testosterone by treatment interactions, all P > 0·35). Blood testosterone concentrations did not correlate with ODI or SpO(2) T90% (all P > 0·19).

CONCLUSIONS

Testosterone therapy in obese men with severe OSA mildly worsens sleep-disordered breathing in a time-limited manner, irrespective of initial testosterone concentrations. This time-dependency was not related to testosterone concentrations.

TRIAL REGISTRATION

www.anzctr.org.au Identifier: ACTRN1260-6000404527.

The hypoxic testicle: physiology and pathophysiology

Mammalian spermatogenesis is a complex biological process occurring in the seminiferous tubules in the testis. This process represents a delicate balance between cell proliferation, differentiation, and apoptosis. In most mammals, the testicles are kept in the scrotum 2 to 7°C below body core temperature, and the spermatogenic process proceeds with a blood and oxygen supply that is fairly independent of changes in other vascular beds in the body. Despite this apparently well-controlled local environment, pathologies such as varicocele or testicular torsion and environmental exposure to low oxygen (hypoxia) can result in changes in blood flow, nutrients, and oxygen supply along with an increased local temperature that may induce adverse effects on Leydig cell function and spermatogenesis. These conditions may lead to male subfertility or infertility. Our literature analyses and our own results suggest that conditions such as germ cell apoptosis and DNA damage are common features in hypoxia and varicocele and testicular torsion. Furthermore, oxidative damage seems to be present in these conditions during the initiation stages of germ cell damage and apoptosis. Other mechanisms like membrane-bound metalloproteinases and phospholipase A2 activation could also be part of the pathophysiological consequences of testicular hypoxia.

Effect of normobaric hypoxia on the testis in a murine model

High-altitude hypoxia generates spermiogram impairment due to germinal epithelium, Leydig cells, sperm and seminal plasma alterations, but precise mechanisms involved are unknown. The objective of this work was to analyse the effect of normobaric hypoxia on the morphology of testicular interstitium and some associated molecular and hormonal factors. Twenty-four mice were exposed to normobaric hypoxia (8.1% inspired oxygen fraction) during 20 days. The effects on body weight, testicular weight, vascularisation, testosterone, HIF1-α and VEGF were analysed at different periods of exposure and compared to controls. Hypoxic mice had lower body weight than mice kept in normoxia. Testicular weight raised significantly the 1st day, but remained normal during the rest of experiment. Number of blood vessels per field and mean diameter of vessels were higher in hypoxic mice. Plasmatic and testicular testosterone raised during first 24 h of hypoxia, but decreased on the 5th day. Vascular/interstitial ratio (proportion of interstice occupied by blood vessels) duplicated at the end of the experiment. Most substantial early effects of hypoxia were testicular oedema, increase in number and diameter of blood vessels and elevation of plasmatic and testicular testosterone. Normobaric hypoxia generates similar effects to those induced by hypobaric hypoxia.

The association of testosterone, sleep, and sexual function in men and women

Testosterone has been the focus of several investigations and review studies in males, but few have addressed its effects on sleep and sexual function, despite evidence of its androgenic effects on circadian activity in both sexes. Studies have been conducted to understand how sleeping increases (and how waking decreases) testosterone levels and how this rhythm can be related to sexual function. This review addresses the inter-relationships among testosterone, sexual function and sleep, including sleep-disordered breathing in both sexes, specifically its effects related to sleep deprivation. In addition, hormonal changes in testosterone that occur in the gonadal and adrenal axis with obstructive sleep apnea and other conditions of chronic sleep deprivation, and which consequently affect sexual life, have also been explored. Nevertheless, hormone-associated sleep disruptions occur across a lifetime, particularly in women. The association between endogenous testosterone and sex, sleep and sleep disturbances is discussed, including the results of clinical trials as well as animal model studies. Evidence of possible pathophysiological mechanisms underlying this relationship is also described. Unraveling the associations of sex steroid hormone concentrations with sleep and sexual function may have clinical implications, as sleep loss reduces testosterone levels in males, and low sex steroid hormone concentrations have been associated with sexual dysfunction.