Higher testosterone is associated with open-angle glaucoma in women: a genetic predisposition?

BACKGROUND

Testosterone may be a possible modifiable risk factor for open-angle glaucoma (OAG) and intraocular pressure (IOP), but evidence has been scarce and conflicting. In this study we evaluated the association of testosterone and its genetic predisposition with incident (i) OAG, IOP, retinal nerve fiber layer (RNFL), and ganglion cell-inner plexiform layer (GCL +).

METHODS

Participants aged 45-100 years were derived from the prospective, population-based Rotterdam Study. Ophthalmic examinations and serum testosterone measurements (including bioavailable and free testosterone) were performed from 1991 onwards. Follow-up took place every 4-5 years. A total of 187 out of 7898 participants were diagnosed with incident (i) OAG during follow-up. Genotyping was performed in 165 glaucoma cases and 6708 controls. We calculated sex-specific weighted genetic risk scores (GRS) for total and bioavailable testosterone. Associations with iOAG were analyzed using multivariable logistic regression. Associations with IOP, RNFL, and GCL + were analyzed with multivariable linear regression. Analyses were stratified on sex and adjusted for at least age, body mass index, and follow-up duration.

RESULTS

In men, testosterone was not associated with iOAG. However, the GRS for higher total testosterone was associated with an increased iOAG risk (odds ratio [OR] with 95% confidence interval [95% CI]: 2.48 [1.18; 5.22], per unit). In women, higher values of bioavailable testosterone (2.05 [1.00; 4.18] per nmol/L) and free testosterone (1.79 [1.00; 3.20] per ng/dL) were significantly associated with increased risk of iOAG. Moreover, the GRS for higher bioavailable testosterone was associated with an increased iOAG risk (2.48 [1.09; 5.65], per unit). Higher bioavailable and free testosterone were adversely associated with IOP (0.58 [0.05; 1.10] per nmol/L and 0.47 [0.04; 0.90] per ng/dL). Higher total testosterone was inversely associated with peripapillary RNFL and GCL + (Beta [95% CI]: - 3.54 [- 7.02; - 0.06] per nmol/L and - 2.18 [- 4.11; - 0.25] per nmol/L, respectively).

CONCLUSIONS

In women, higher testosterone levels increased the risk of iOAG. Both IOP-dependent and IOP-independent mechanisms may underlie this association. Managing testosterone levels may be particularly relevant for the prevention of neurodegeneration in the eye. Future research should confirm these findings.

Frailty and testosterone level in older adults: a systematic review and meta-analysis

PURPOSE

We conducted a systematic review to evaluate the relationship between total testosterone (TT), free testosterone (fT), or sex hormone-binding globulin (SHBG) and frailty in older adults.

METHODS

We systematically searched nine databases (e.g. MEDLINE, Embase, ACP Journal Club, and the Cochrane library et al.) for papers on frailty and androgen levels published up to October 10, 2021. We calculated the odds ratio (OR) for the relationship between testosterone level and frailty by performing meta-analysis.

RESULTS

The search strategy yielded 311 hits in all databases combined. Eleven (seven cross-sectional studies and four cohort studies) met the inclusion criteria for meta-analysis. Among cross-sectional studies, meta-analysis revealed a significant association between TT and frailty in men (OR = 1.37 [95% CI 1.09, 1.72]) not women (OR = 1.06 [0.84, 1.34]). The fT was also significantly association with frailty in men (OR = 1.55 [1.06, 2.25] not women (OR = 1.35 [0.91, 2.01]). Cohort studies showed the same result in TT (OR = 1.09 [1.02, 1.18]) and fT (OR = 1.15 [1.02, 1.30]) for men. We did not find a significant association between SHBG and frailty.

CONCLUSION

The findings of this systematic review and meta-analysis suggest that TT and fT were significantly associated with frailty in older men but not women.

Advances in stem cell research for the treatment of primary hypogonadism

In Leydig cell dysfunction, cells respond weakly to stimulation by pituitary luteinizing hormone, and, therefore, produce less testosterone, leading to primary hypogonadism. The most widely used treatment for primary hypogonadism is testosterone replacement therapy (TRT). However, TRT causes infertility and has been associated with other adverse effects, such as causing erythrocytosis and gynaecomastia, worsening obstructive sleep apnoea and increasing cardiovascular morbidity and mortality risks. Stem-cell-based therapy that re-establishes testosterone-producing cell lineages in the body has, therefore, become a promising prospect for treating primary hypogonadism. Over the past two decades, substantial advances have been made in the identification of Leydig cell sources for use in transplantation surgery, including the artificial induction of Leydig-like cells from different types of stem cells, for example, stem Leydig cells, mesenchymal stem cells, and pluripotent stem cells (PSCs). PSC-derived Leydig-like cells have already provided a powerful in vitro model to study the molecular mechanisms underlying Leydig cell differentiation and could be used to treat men with primary hypogonadism in a more specific and personalized approach.

Diagnosis of hypogonadism in patients treated with low energy shock wave therapy for erectile dysfunction: a narrative review

Several methods of treatment of erectile dysfunction (ED) are offered with low energy shock-wave therapy (LESWT) gaining increasing attention. Reports have documented that LESWT stimulates tissue neovascularization, proliferation and differentiation of endothelial cells, and production of nitric oxide - all can improve the condition of erectile tissue. However, the overall and sexual condition of men deteriorates with age which is linked with a constant decrease in testosterone concentration. A higher risk of sexual health disorders and reduced physical fitness correlates with a testosterone concentration of <12 nmol/L. Such patients may require testosterone replacement therapy. We conducted a target literature review to investigate whether testosterone concentration is taken into account in studies on the use of LESWT in the treatment of ED. We found that most studies did not provide any information on testosterone status. Only 8 of 25 studies examined showed values of testosterone concentrations. Only one of these analyses checked the relationship between the efficacy of LESWT and testosterone concentration. As a result, meta-analyses published to date may not show the full value of LESWT in the treatment of ED. We conclude that in the light of the significant role testosterone plays in the process of an erection and the mechanism of LESWT action, it can be recommended to examine testosterone concentration and to diagnose hypogonadism during the qualification of patients to studies on LESWT efficacy. Moreover, the effectiveness of LESWT in relation to the current testosterone concentration should also be further investigated.

Osteoporosis from an Endocrine Perspective: The Role of Hormonal Changes in the Elderly

Introduction: Osteoporosis is increasingly prevalent in the elderly, with fractures mostly occurring in women and men who are older than 55 and 65 years of age, respectively. The aim of this review was to examine the evidence regarding the influence of hormones on bone metabolism, followed by clinical data of hormonal changes in the elderly, in the attempt to provide possible poorly explored diagnostic and therapeutic candidate targets for the management of primary osteoporosis in the aging population. Material and methods: An extensive Medline search using PubMed, Embase, and Cochrane Library was performed. Results: While the rise in Thyroid-stimulating hormone (TSH) levels has a protective role on bone mass, the decline of estrogen, testosterone, Insulin-like growth factor 1 (IGF1), and vitamin D and the rise of cortisol, parathyroid hormone, and follicle-stimulating hormone (FSH) favor bone loss in the elderly. Particularly, the AA rs6166 FSH receptor (FSHR) genotype, encoding for a more sensitive FSHR than that encoded by the GG one, is associated with low total body mass density (BMD), independently of circulating estrogen. A polyclonal antibody with a FSHR-binding sequence against the β-subunit of murine FSH seems to be effective in ameliorating bone loss in ovariectomized mice. Conclusions: A complete hormonal assessment should be completed for both women and men during bone loss evaluation. Novel possible diagnostic and therapeutic tools might be developed for the management of male and female osteoporosis.

Association of total testosterone, free testosterone, bioavailable testosterone, sex hormone-binding globulin, and hypertension

Low testosterone has been inversely associated with hypertension. Our objective was to determine the associations between total testosterone (TT), free testosterone (FT), bioavailable testosterone (BioT), sex hormone-binding globulin (SHBG), and hypertension. Two hundred fifty-three men were enrolled in this study. TT and SHBG were measured by chemiluminescent immunoassay, and FT and BioT were calculated. Hypertension was defined as systolic blood pressure (SBP) ≥140 mm Hg and/or diastolic blood pressure (DBP) ≥90 mm Hg. Our results showed that hypertensive men had higher SHBG levels, and lower FT and BioT, compared to normotensive men. FT and BioT were inversely associated with SBP and DBP after adjusting for covariates (age, smoking, alcohol consumption, and physical activity). Furthermore, there was a significant decrease in the odds ratios for hypertension in the third and fourth quartiles of BioT and FT, compared to the lowest quartile before and after adjusting for covariates. In contrast, the OR for hypertension in the third quartile of SHBG was lower than the highest quartile. Our data show that FT and BioT are inversely correlated with SBP, DBP, and hypertension in men.

Association of total testosterone, free testosterone, bioavailable testosterone and sex hormone-binding globulin with hepatic steatosis and the ratio of aspartate aminotransferase to alanine aminotransferase

Several articles have shown the inverse association between total testosterone (TT) or sex hormone-binding globulin (SHBG) and hepatic steatosis. No articles report associations of TT, SHBG, free testosterone (FT), and bioavailable testosterone (BioT) with aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratios. Therefore, we investigated the associations of TT, FT, BioT and SHBG with hepatic steatosis and AST/ALT ratios. A total of 218 men were enrolled. We diagnosed hepatic steatosis by ultrasound. TT and SHBG showed a reduced risk for hepatic steatosis when analyzed with or without adjusting for age, smoking, alcohol consumption and physical activity. Compared with the lowest quartile, the ORs for hepatic steatosis in the third and fourth quartiles (0.32 [95% CI: 0.14-0.75] and 0.27 [95% CI: 0.10-0.73], respectively) of SHBG were significantly lower after adjustments. The OR for hepatic steatosis in the fourth quartile of TT (0.41 [95% CI: 0.17-0.95]) was significantly lower than in the lowest quartile after adjustments. The mean AST/ALT ratios in men with hepatic steatosis were lower than those without hepatic steatosis (0.83 and 1.04, respectively), due to the elevated ALT levels in hepatic steatosis groups. Furthermore, TT and SHBG were positively associated with AST/ALT ratios with and without adjustments. In conclusion, higher TT and SHBG levels in men are associated with the reduced risk of hepatic steatosis and elevated AST/ALT ratios, independent of age, smoking, alcohol consumption and physical activity.

New Biomarkers to Evaluate Hyperandrogenemic Women and Hypogonadal Men

Androgens can have variable effects on men and women. Women may be evaluated for androgen excess for several reasons. Typically, young premenopausal women present with clinical symptoms of hirsutism, alopecia, irregular menses, and/or infertility. The most common cause of these symptoms is polycystic ovary syndrome. After menopause, even though ovaries stop producing estrogen, they continue to produce androgen, and women can have new onset of hirsutism and alopecia. Laboratory evaluation involves measurement of the major ovarian and adrenal androgens. In women, age, phase of the menstrual cycle, menopausal status, obesity, metabolic health, and sex hormone-binding proteins significantly affect total-androgen levels and complicate interpretation. This review will summarize the clinically relevant evaluation of hyperandrogenemia at different life stages in women and highlight pitfalls associated with interpretation of commonly used hormone measurements. Hypogonadism in men is a clinical syndrome characterized by low testosterone and/or low sperm count. Symptoms of hypogonadism include decreased libido, erectile dysfunction, decreased vitality, decreased muscle mass, increased adiposity, depressed mood, osteopenia, and osteoporosis. Hypogonadism is a common disorder in aging men. Hypogonadism is observed rarely in young boys and adolescent men. Based on the defects in testes, hypothalamus, and/or pituitary glands, hypogonadism can be broadly classified as primary, secondary, and mixed hypogonadism. Diagnosis of hypogonadism in men is based on symptoms and laboratory measurement. Biomarkers in use/development for hypogonadism are classified as hormonal, Leydig and Sertoli cell function, semen, genetic/RNA, metabolic, microbiome, and muscle mass-related. These biomarkers are useful for diagnosis of hypogonadism, determination of the type of hypogonadism, identification of the underlying causes, and therapeutic assessment. Measurement of serum testosterone is usually the most important single diagnostic test for male hypogonadism. Patients with primary hypogonadism have low testosterone and increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Patients with secondary hypogonadism have low testosterone and low or inappropriately normal LH and FSH. This review provides an overview of hypogonadism in men and a detailed discussion of biomarkers currently in use and in development for diagnosis thereof.

Risk factors for late-onset hypogonadism

The European Male Aging Study (EMAS) has recently defined strict diagnostic criteria for late-onset hypogonadism (LOH) including the levels of serum total testosterone (TT), free testosterone (FT) and three sexual symptoms. However, there is no report on risk factors for LOH using these criteria. In this study, we investigated risk factors for LOH based on these criteria. We recruited 277 men (aged 36-80 years) who completed both a health check-up and two questionnaires (a health and lifestyle questionnaire, and a sexual function questionnaire). Data on parameters, such as systolic blood pressure (SBP), glucose, triglyceride (TG) and high-density lipoprotein (HDL), were obtained from medical records of the hospital in Shantou. TT and sex hormone-binding globulin (SHBG) were measured by chemiluminescent immunoassay, and FT was calculated. TT, FT, age, waist circumference, SBP and glucose showed significant differences between LOH-positive and LOH-negative individuals. Univariate regression analyses showed that age, waist circumference, SBP, glucose and health status were risk factors for LOH. Pearson's correlation analysis revealed that TT was inversely correlated with waist circumference, glucose and SBP, and FT was inversely correlated with age, SBP and health status. In conclusion, age, waist circumference, SBP, glucose and health status were risk factors for LOH.

Andropause - state of the art 2015 and review of selected aspects

The term ‘male menopause’ was first used in 1944 to describe various complaints of ageing men which at least partially mirrored the climacteric symptoms in women. Continuous research resulted in the evolution of opinions about the nature of these complaints, from the clinical syndrome, diagnosed with the use of disease-targeted questionnaires, to a well-defined clinical and biochemical syndrome. The pathophysiological causes – gonad ageing (with a compensatory rise in luteinizing hormone), age-related increase in serum sex hormone-binding globulin (SHBG) levels, the role of visceral adipose tissue as a place for aromatization of androgen to estrogen, and lower sensitivity of testosterone receptors – have been described. However, no consensus was reached as far as the definition, incidence, treatment, and especially testosterone therapy, are concerned. Our review presents the current standpoints, indicating the predictive role of late-onset hypogonadism (LOH) in evaluating male health as well as the current literature reports on the risks and benefits of using testosterone therapy.

Leydig cell aging and hypogonadism

Leydig cell testosterone (T) production is reduced with age, resulting in reduced serum T levels (hypogonadism). A number of cellular changes have been identified in the steroidogenic pathway of aged Leydig cells that are associated with reduced T formation, including reductions in luteinizing hormone (LH)-stimulated cAMP production, the cholesterol transport proteins steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and downstream steroidogenic enzymes of the mitochondria and smooth endoplasmic reticulum. Many of the changes in steroid formation that characterize aged Leydig cells can be elicited by the experimental alteration of the redox environment of young cells, suggesting that changes in the intracellular redox balance may cause reduced T production. Hypogonadism is estimated to affect about 5 million American men, including both aged and young. This condition has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass, reduced bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Exogenous T administration is now used widely to elevate serum T levels in hypogonadal men and thus to treat symptoms of hypogonadism. However, recent evidence suggests that men who take exogenous T may face increased risk of stroke, heart attack, and prostate tumorigenesis. Moreover, it is well established that administered T can have suppressive effects on LH, resulting in lower Leydig cell T production, reduced intratesticular T concentration, and reduced spermatogenesis. This makes exogenous T administration inappropriate for men who wish to father children. There are promising new approaches to increase serum T by directly stimulating Leydig cell T production rather than by exogenous T therapy, thus potentially avoiding some of its negative consequences.

Pharmacological regulation of the cholesterol transport machinery in steroidogenic cells of the testis

Reduced serum testosterone (T), or hypogonadism, is estimated to affect about 5 million American men, including both aging and young men. Low serum T has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass and bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Administering exogenous T, known as T-replacement therapy (TRT), reverses many of the symptoms of low T levels. However, this treatment can result in luteinizing hormone suppression which, in turn, can lead to reduced sperm numbers and infertility, making TRT inappropriate for men who wish to father children. Additionally, TRT may result in supraphysiologic T levels, skin irritation, and T transfer to others upon contact; and there may be increased risk of prostate cancer and cardiovascular disease, particularly in aging men. Therefore, the development of alternate therapies for treating hypogonadism would be highly desirable. To do so requires greater understanding of the series of steps leading to T formation and how they are regulated, and the identification of key steps that are amenable to pharmacological modulation so as to induce T production. We review herein our current understanding of mechanisms underlying the pharmacological induction of T formation in hypogonadal testis.

Late-onset hypogonadism: current concepts and controversies of pathogenesis, diagnosis and treatment

Although suppressed serum testosterone (T) is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual (e.g., erectile dysfunction), physical (e.g. loss of vigor and frailty) and psychological (e.g., depression) symptoms. This syndrome carries many names, including male menopause or climacterium, andropause and partial androgen deficiency of the ageing male (PADAM). Late-onset hypogonadism (LOH) describes it best and is therefore generally preferred. The decrease of T in LOH is often marginal, and hypogonadism can be either due to primary testicular failure (low T, high luteinizing hormone (LH)) or secondary to a hypothalamic-pituitary failure (low T, low or inappropriately normal LH). The latter form is more common and it is usually associated with overweight/obesity or chronic diseases (e.g., type 2 diabetes mellitus, the metabolic syndrome, cardiovascular and chronic obstructive pulmonary disease, and frailty). A problem with the diagnosis of LOH is that often the symptoms (in 20%–40% of unselected men) and low circulating T (in 20% of men >70 years of age) do not coincide in the same individual. The European Male Ageing Study (EMAS) has recently defined the strict diagnostic criteria for LOH to include the simultaneous presence of reproducibly low serum T (total T <11 nmol l⁻¹ and free T <220 pmol l⁻¹) and three sexual symptoms (erectile dysfunction, and reduced frequency of sexual thoughts and morning erections). By these criteria, only 2% of 40- to 80-year-old men have LOH. In particular obesity, but also impaired general health, are more common causes of low T than chronological age per se. Evidence-based information whether, and how, LOH should be treated is sparse. The most logical approach is lifestyle modification, weight reduction and good treatment of comorbid diseases. T replacement is widely used for the treatment, but evidence-based information about its real benefits and short- and long-term risks, is not yet available. In this review, we will summarize the current concepts and controversies in the pathogenesis, diagnosis and treatment of LOH.

Clinical biochemistry of dihydrotestosterone

Dihydrotestosterone (DHT) is the most potent natural androgen in humans. There has been an increasing interest in this androgen and its role in the development of primary and secondary sexual characteristics as well as its potential roles in diseases ranging from prostate and breast cancer to Alzheimer's disease. Despite the range of pathologies shown to involve DHT there is little evidence for measurement of serum DHT in the management of these diseases. In this review we describe the physiology of DHT production and action, summarize current concepts in the role of DHT in the pathogenesis of various disorders of sexual development, compare current methods for the measurement of DHT and conclude on the clinical utility of DHT measurement. The clinical indications for the measurement of DHT in serum are: investigation of 5α reductase deficiency in infants with ambiguous genitalia and palpable gonads; men with delayed puberty and/or undescended testes; and to confirm the presence of active testicular tissue. Investigation is aided by the use of human chorionic gonadotrophin stimulation. Due to paucity of published data on this procedure, it is important to follow guidelines prescribed by the laboratory performing the analysis to ensure accurate interpretation.

Challenges for the endocrine laboratory in critical illness

The endocrine laboratory must provide accurate and timely results for the critically ill patient. A number of pathophysiological factors affect assay systems for adrenal, thyroid and gonadal function tests. The effects are primarily on estimates of 'free hormone' concentration through abnormal binding protein concentrations and the effects of drugs and metabolites on hormone-protein binding. The limitations of the principal analytical techniques (immunoassay and chromatography-mass spectrometry) include drug effects, endogenous antibody interference and ion suppression. These effects are not always easily identified. Analytical specificity and standardisation result in differences in bias between assays and thus a requirement for assay specific decision limits and reference ranges. Good communication between clinician and laboratory is needed to minimise these effects. Developments in mass spectrometry should lead to greater sensitivity and wider applicability of the technique. International efforts to develop higher order reference materials and reference method procedures should lead to greater comparability of results.

Male late-onset hypogonadism: pathogenesis, diagnosis and treatment

Some aging men develop a condition of suppressed serum testosterone levels, which is associated with diffuse sexual, physical and psychological symptoms. Several terms are used for this syndrome, but late-onset hypogonadism (LOH) is preferred. The diagnosis of LOH is often uncertain because symptoms (occurring in 20-40% of men) and low circulating testosterone (found in 20% of men >70 years of age) seldom occur together. The strict diagnostic criteria for LOH include reproducibly low serum testosterone levels and sexual symptoms, including erectile dysfunction and reduced frequency of sexual thoughts and morning erections. Using these diagnostic criteria, only 2% of 40-80-year-old men have LOH. Obesity and impaired general health (including diabetes mellitus, cardiovascular and chronic obstructive pulmonary disease, and frailty) are more common reasons for low testosterone than advanced age per se. It seems logical, therefore, to begin by treating these conditions before testosterone replacement therapy is initiated. Even then, testosterone should only be used if there are no contraindications, such as unstable cardiac disease, serious prostate symptoms and high hemoglobin level. The long-term benefit of testosterone replacement therapy is uncertain, and the experimental nature of the treatment, and its associated risks, must be fully explained to the patient before treatment begins.