Anti-Müllerian hormone and inhibin B levels reflect altered Sertoli cell function in men with metabolic syndrome

AMH in Males: Effects of Body Size and Composition on Serum AMH Levels

Serum concentrations of anti-Müllerian hormone (AMH) have been found to decrease with increasing body mass index (BMI) in many studies. It is not yet clear whether this stems from an adverse effect of adiposity on AMH production, or from dilution due to the greater blood volume that accompanies a larger body size. To investigate a possible hemodilution effect, we explored the relationships between serum AMH levels and different parameters of body composition using linear regression models in a cohort of adult males. Body weight, lean mass (LM), and body surface area (BSA) were found to be better predictors of AMH than measures of adiposity, such as BMI or fat mass. Since both LM and BSA correlate with plasma volume better than adipose tissue, we conclude that hemodilution of AMH does occur in adult males and should be considered for normalization in future studies.

High serum alpha-fetoprotein levels in primary infertile men

BACKGROUND

Alfa-fetoprotein (AFP) is a serum glycoprotein highly produced during fetal development. While AFP synthesis drops dramatically after birth, AFP production only persists or returns under specific pathological condition.

OBJECTIVE

We sought to investigate the rate of and the potential meaning of high AFP serum levels in men seeking first medical attention for couple's primary infertility.

MATERIALS AND METHODS

Socio-demographic and clinical data from 1803 non-Finnish, White-European primary infertile men were retrospectively analysed. AFP was routinely measured in each patient (high AFP was defined as >7 ng/ml). Men with history of liver diseases, testicular cancer, or other known causes of increased AFP levels were excluded from the final analysis. Semen analyses were based on the 2010 World Health Organization reference criteria. Descriptive statistics and logistic regression models tested the association between serum AFP and clinical variables. Possible nonlinear relationships were graphically explored with locally estimated scatterplot smoothing method.

RESULTS

Overall, high serum AFP level was found in 29 (1.7%) patients. Normal versus high AFP levels patients were comparable in terms of body mass index (BMI), Charlson Comorbidity Index, waist circumference, smoking habits, history of cryptorchidism, testicular volume, and serum hormones (i.e., follicle-stimulating hormone, luteinizing hormone, and total testosterone). Conversely, men with higher AFP levels were older (p = 0.02), had lower sperm concentration (p = 0.003), and were more frequently oligozoospermic and azoospermic (all p ≤ 0.03). At multivariate analysis, high AFP levels were independently associated with oligozoospermia (OR 3.79; p = 0.033) and azoospermia (OR 3.29; p = 0.006). Likewise, if AFP levels increase, patients were found to be older, with higher BMI and to have more comorbidities (all p < 0.05).

DISCUSSION

Unexplained high AFP levels account for almost 2% of cases in primary infertile patients without a previous history of associated disorders. Higher serum AFP levels are linked with aberrant sperm counts, older age, obesity, and a greater amount of comorbid conditions.

CONCLUSION

Despite the need for additional validation, these data suggest that serum AFP measurement might have a multifaceted role over the diagnostic work-up of males presenting for couple's infertility.

The effects of different physiologic concentrations of prolactin in association with reproductive hormones on the incidence of type 2 diabetes mellitus in men: Tehran Lipid and Glucose Study

BACKGROUND

Data is inconsistent and, for the most part, not sufficient to demonstrate the association between serum Prolactin (PRL) concentration within the physiologic range and the incidence rate of type 2 Diabetes Mellitus (DM) among men. Moreover, since both PRL and type 2 DM are associated with reproductive hormones, investigating these hormones might improve our understanding of how PRL might impose its effect on the incidence rate of type 2 DM.

METHODS

For the present study, 652 eligible men aged 29-70 with a normal baseline PRL concentration were selected from the Tehran Lipid and Glucose Study (TLGS). Participants were sub-classified into three groups (tertiles) according to the serum concentration of PRL and were followed for 15.8 years. The incidence of type 2 DM and PRL, LH, FSH, testosterone, and AMH concentrations were measured. The effect of hormonal variables on the incidence of type 2 DM was estimated using the log-binomial model, adjusted for major confounding factors. The correlations between PRL and the indicators of glucose and lipid metabolism and other hormonal variables were also explored.

RESULTS

In the unadjusted model, PRL was not significantly associated with the incidence rate of type 2 DM (RR = 0.98, 95% CI: 0.94 - 1.03). After adjusting for potential confounders, the inverse effect of AMH on the incidence rate of type 2 DM was the only significant association. The analyses also indicated a significant positive association between PRL and LH/FSH ratio (r = 0.1, P = 0.01).

CONCLUSION

No significant association was found between serum PRL concentrations within the physiologic range and the incidence rate of type 2 diabetes mellitus among middle-aged men. Men with higher concentrations of PRL within the physiologic range tended to show higher levels of LH and LH/FSH. AMH was the only variable significantly linked to the incidence rate of type 2 DM in men.

Anti-Müllerian hormone concentration is associated with central adiposity and reproductive hormones in expectant fathers

OBJECTIVE

The role of the anti-Müllerian hormone (AMH) as an indicator of physical and reproductive health in men is unclear. We assessed the relationships between AMH and follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and metabolic parameters, in a cohort of expectant fathers.

DESIGN

ORIGINS Project prospective cohort study.

SETTING

Community-dwelling men.

PARTICIPANTS

Partners of pregnant women attending antenatal appointments.

MAIN OUTCOME MEASURES

Serum AMH, FSH, LH, testosterone, and metabolic parameters.

RESULTS

In 485 expectant fathers, median age 33 years, median AMH was 40 pmol/L (quartiles 29, 56). AMH was inversely correlated with FSH, age, and body mass index (BMI) (correlation coefficients: -.32, -.24, and -.17 respectively). The age association was nonlinear, with peak AMH between 20 and 30 years, a decline thereafter, and somewhat steady levels after 45 years. The inverse association of AMH with FSH was log-linear and independent of age and BMI (β: -.07, SE: 0.01, p &lt; .001). AMH was inversely correlated with waist circumference and directly associated with sex hormone-binding globulin. Testosterone was moderately correlated with AMH (correlation coefficient: .09, β: .011, SE: 0.004, p = .014): this association was mediated by an inverse relationship with BMI (mediated proportion 0.49, p &lt; .001).

CONCLUSIONS

In reproductively active men, lower AMH is a biomarker for advancing age, and for poorer metabolic and reproductive health. The inverse association between AMH and FSH is independent of age and BMI, whereas the association of AMH and testosterone is mediated via BMI. The utility of AMH to predict reproductive and cardiometabolic outcomes in men warrants further investigation.

Inherited Metabolic Memory of High-fat Diet Impairs Testicular Fatty Acid Content and Sperm Parameters

Exposure to a high-fat diet (HFD) from early-life is associated with a testicular metabolic signature linked to abnormal sperm parameters up to two generations after exposure in mice. Hereby, we describe a testicular lipid signature associated with "inherited metabolic memory" of exposure to HFD, persisting up to two generations in mice. Diet-challenged mice (n = 36) were randomly fed after weaning with standard chow (CTRL); HFD for 200 days or transient HFD (HFD_t ) (60 days of HFD+140 days of standard chow). Subsequent generations (36 mice per generation) were fed with chow diet. Mice were euthanized 200 days post-weaning. Glucose homeostasis, serum hormones, testicular bioenergetics and antioxidant enzyme activity were evaluated. Testicular lipid-related metabolites and fatty acids were characterized by ¹ H-NMR and GC-MS. Sons of HFD display impaired choline metabolism, mitochondrial activity and antioxidant defenses, while grandsons show a shift in testicular ω3/ω6 ratio towards a pro-inflammatory environment. Grandsons of HFDt raise 3-hydroxybutyrate levels with possible implications to testicular insulin resistance. Sperm counts decrease in grandsons of HFD-exposed mice, regardless of the duration of exposure. HFD-induced "inherited metabolic memory" alters testicular fatty acid metabolism with consequences to sperm parameters up to two generations. This article is protected by copyright. All rights reserved.

Anti-Müllerian hormone levels and risk of type 2 diabetes in women

AIMS/HYPOTHESIS

Given its role in ovarian follicle development, circulating anti-Müllerian hormone (AMH) is considered to be a marker of reproductive ageing. Although accelerated reproductive ageing has been associated with a higher risk of type 2 diabetes, research on the relationship between AMH and type 2 diabetes risk is scarce. Therefore, we aimed to investigate whether age-specific AMH levels and age-related AMH trajectories are associated with type 2 diabetes risk in women.

METHODS

We measured AMH in repeated plasma samples from 3293 female participants (12,460 samples in total), aged 20-59 years at recruitment, from the Doetinchem Cohort Study, a longitudinal study with follow-up visits every 5 years. We calculated age-specific AMH tertiles at baseline to account for the strong AMH-age correlation. Cox proportional hazards models adjusted for confounders were used to assess the association between baseline age-specific AMH tertiles and incident type 2 diabetes. We applied linear mixed models to compare age-related AMH trajectories for women who developed type 2 diabetes with trajectories for women who did not develop diabetes.

RESULTS

During a median follow-up of 20 years, 163 women developed type 2 diabetes. Lower baseline age-specific AMH levels were associated with a higher type 2 diabetes risk (HR_T2vsT3 1.24 [95% CI 0.81, 1.92]; HR_T1vsT3 1.62 [95% CI 1.06, 2.48]; p_trend = 0.02). These findings seem to be supported by predicted AMH trajectories, which suggested that plasma AMH levels were lower at younger ages in women who developed type 2 diabetes compared with women who did not. The trajectories also suggested that AMH levels declined at a slower rate in women who developed type 2 diabetes, although differences in trajectories were not statistically significant.

CONCLUSIONS/INTERPRETATION

We observed that lower age-specific AMH levels were associated with a higher risk of type 2 diabetes in women. Longitudinal analyses did not show clear evidence of differing AMH trajectories between women who developed type 2 diabetes compared with women who did not, possibly because these analyses were underpowered. Further research is needed to investigate whether AMH is part of the biological mechanism explaining the association between reproductive ageing and type 2 diabetes. Graphical abstract.

Anti-Müllerian hormone (AMH) concentrations are maximal at puberty in male donkeys and secretion is redirected from the blood stream to seminal plasma

Sertoli cells produce anti-Müllerian hormone (AMH) and number of these cells is associated with numbers of sperm produced. The study aim was to quantify AMH concentrations in serum and seminal plasma of donkeys during puberty, and to correlate the values with those for testicular width and semen quality of sexually mature males. Blood was collected from five donkeys every second month from 4 to 24 months of age, and then once at 40 months of age. Semen was collected once monthly, from 13 to 19 and 23-25 months of age. There was quantification of AMH concentrations in serum and seminal plasma. During puberty, there was a redirection of AMH secretion from the blood stream into seminal plasma. In serum, AMH concentrations increased during puberty with a maximal concentration at 16 months and the changes were similar for seminal plasma with a maximal concentration at 18 months of age. Serum AMH concentrations from 14-20 were greater than at 12 or 22 months of age. Maximal serum AMH concentrations were associated with testicular width at 24 months (r = 0.97, P = 0.005), but not with sperm count, sperm motility or percentage of sperm with normal morphology at 42 months of age. There were no significant correlations among values for AMH concentrations in seminal plasma during puberty and values for any of the seminal variables.

Effect of clomiphene citrate treatment on the Sertoli cells of dysmetabolic obese men with low testosterone levels

BACKGROUND

Clomiphene citrate (CC) has been shown to restore the hypothalamic-pituitary-gonadal (HPG) axis by increasing testosterone (T) levels to physiological levels in patients with dysmetabolic conditions such as obesity, metabolic syndrome and type 2 diabetes mellitus (T2DM). However, the data are unclear regarding the effects on Sertoli cell (SC) function.

AIM

To study SC function by assessing Inhibin B (IB) and anti-Mullerian hormone (AMH) levels at baseline and after 3 months of CC treatment.

MATERIALS AND METHODS

This is an ancillary study of a cross-over, randomised, double-blind, placebo-controlled trial performed to evaluate androgen response to CC treatment in dysmetabolic obese subjects with low T levels treated with metformin. We evaluated SC function by assessing IB and AMH levels at baseline and after 3 months of each treatment in ten dysmetabolic obese subjects with low T levels. In all subjects, the influence of the clinical characteristics, metabolic and hormonal baseline parameters on SC and Leydig (LC) function, evaluated respectively with AMH, IB, follicle-stimulating hormone (FSH) and T levels, was tested.

RESULTS

No significant changes were observed for IB and AMH concentrations after each treatment period. Whereas T and oestradiol (E2) levels were shown to be significantly higher in the CC plus metformin phase (CC/Met) only. No clinical, metabolic or hormonal parameters showed significant effects on serum AMH at baseline or after treatments. However, baseline T, dihydrotestosterone (DHT) and E2 positively affected IB levels during CC/Met therapy (P = .003, P = .038 and P = .049, respectively). Baseline leptin and FSH had a negative (P = 031) and positive (P = .048) respectively role on T levels during CC/Met, as they were statistically significant compared to the placebo period (Plac/Met).

CONCLUSION

Unlike the LC activity, CC was unable to influence SC function, as shown by the lack of IB and AMH serum modifications, thus suggesting an intrinsic nonreversible defect of SC cells in patients with dysmetabolic conditions.

Adipocytokines may delay pubertal maturation of human Sertoli cells

Reproduction is an important target of obesity complications, including adverse effects on spermatogenesis and steroidogenesis. Adipocytokines are key mediators in various complications of obesity. Our aim was to study the potential of adipocytokines to affect Sertoli cell function, which is crucial for spermatogenesis, and possibly link these findings to the observed attenuation of spermatogenesis in obese males. Testicular biopsies were obtained from healthy donors. Highly purified adult human Sertoli cells (HSCs) were isolated by fluorescence-activated cell sorting. Cells were cultured and exposed to different concentrations of adipocytokines (10-1000ngmL-1 ) for 2-7 days. Expression of selected Sertoli cell genes was quantified by quantitative polymerase chain reaction. Long-term treatment (7 days) of HSCs with higher concentrations of chemerin, irisin, nicotinamide phosphoribosyltransferase (Nampt), resistin and progranulin significantly suppressed FSH receptor expression (by 79%, 83%, 64%, 71% and 26% respectively; P P invitro , may negatively affect Sertoli cell maturation and retain these cells in a more prepubertal stage. This could negatively affect testis function and add to fertility problems in obese adults.

Sertoli Cell Function in Young Males with Metabolic Syndrome

CONTEXT

The last few decades have witnessed an alarming increase in the prevalence of the metabolic syndrome (MetS) worldwide including India. Apart from the known risks of MetS in terms of cardiovascular risk and mortality, there is increasing evidence that it also leads to alteration in testicular function and fertility.

AIMS

To assess the presence of hypogonadism and Sertoli cell dysfunction in young adult males with MetS and correlate these parameters with different components of the MetS.

SETTINGS AND DESIGN

Cross-sectional study conducted in the Department of Endocrinology, Gauhati Medical College, a tertiary care hospital in North East India.

SUBJECTS AND METHODS

Young adult males with MetS aged 20-40 years and age-matched healthy males who served as controls were examined clinically. Laboratory investigations done in the fasting state included blood glucose, lipid profile, serum follicle-stimulating hormone (FSH), inhibin B and total testosterone (Te). Semen was collected after 3 days abstinence and analysis done.

STATISTICAL ANALYSIS

Baseline parameters were presented as median and 'Kruskal-Wallis' test was used to compare them. Pearson test and multiple regression analysis were used to assess the correlation and association between variables.

RESULTS

Fifty cases with MetS and 30 controls were included in the study. Subjects with MetS had significantly lower levels of total Te, FSH and inhibin B. They also had significantly lower semen volume, sperm count and total as well as progressive motility. There was a significant negative correlation of waist circumference and positive correlation of inhibin B with total sperm count. A significant negative association of serum triglycerides with semen volume was also found.

CONCLUSION

MetS is a state of hypogonadotropic hypogonadism as reflected by low total Te, FSH and inhibin B levels with semen abnormalities reflecting Sertoli cell dysfunction.

Pubertal Status and Gonadal Functions in Obese Boys with Fatty Liver

BACKGROUND

In adult studies, obese subjects with nonalcoholic fatty liver disease (NAFLD) have been shown to have poor sperm quality, and lower testosterone and luteinizing hormone levels. The aim of this study was to investigate the pubertal status and gonadal functions in obese boys with NAFLD.

MATERIALS AND METHODS

The study included 119 obese and 78 nonobese age-matched adolescents. The obese boys were separated into two groups based on the presence (NAFLD group) or absence of liver steatosis with high transaminases (non-NAFLD group). The levels of serum AMH (anti-Mullerian hormone), inhibin B, gonadotropins, total testosterone, lipids, high-sensitivity C-reactive protein, fasting glucose, insulin levels, and aortic intima media thickness were measured in all subjects.

RESULTS

Of the total 197 children, 174 had reached puberty. There were no significant differences between the groups in respect of testicular sizes and the prevalence of pubertal status among the groups (84.3% of NAFLD vs. 70.6% of non-NAFLD vs. 98.7% of control subjects). No significant differences were found in respect of gonadotropins and AMH levels. Total testosterone levels in the NAFLD group were significantly lower than those of the non-NAFLD obese group (P < 0.001) and the control group (P < 0.001). Inhibin B levels were also significantly lower in all (NAFLD and non-NAFLD) obese groups compared to the control group (P = 0.008).

CONCLUSIONS

The results of the study demonstrated that diminished testosterone and inhibin B levels occur in pubertal obese boys with NAFLD. No significant differences were detected according to pubertal status, AMH levels, and testicular volumes in the age-matched groups.

The effects of the obesogen tributyltin on the metabolism of Sertoli cells cultured ex vivo

Human exposure to environmental contaminants is widespread. Some of these contaminants have the ability to interfere with adipogenesis, being thus considered as obesogens. Recently, obesogens have been singled out as a cause of male infertility. Sertoli cells (SCs) are essential for male fertility and their metabolic performance, especially glucose metabolism, is under a tight endocrine control, being essential for the success of spermatogenesis. Herein, we studied the impact of the model obesogen tributyltin in the metabolic profile of SCs. For that, ex vivo-cultured rat SCs were exposed to increasing doses of tributyltin. SCs proliferation was evaluated by the sulforhodamine B assay and the maturation state of the cells was assessed by the expression of specific markers (inhibin B and the androgen receptor) by quantitative polymerase chain reaction. The metabolic profile of SCs was established by studying metabolites consumption/production by nuclear magnetic resonance spectroscopy and by analyzing the expression of key transporters and enzymes involved in glycolysis by Western blot. The proliferation of SCs was only affected in the cells exposed to the highest dose (1000 nM) of tributyltin. Notably, SCs exposed to 10 nM tributyltin decreased the consumption of glucose and pyruvate, as well as the production of lactate. The decreased lactate production hampers the development of germ cells. Intriguingly, the lowest levels of tributyltin were more prone to modulate the expression of key players of the glycolytic pathway. This is the first study showing that tributyltin reprograms glucose metabolism of SCs under ex vivo conditions, suggesting new targets and mechanisms through which obesogens modulate the metabolism of SCs and thus male (in)fertility.

Metabolic syndrome in White-European men presenting for secondary couple's infertility: an investigation of the clinical and reproductive burden

We aimed to determine the impact of metabolic syndrome (MetS) on reproductive function in men with secondary infertility, a condition that has received relatively little attention from researchers. Complete demographic, clinical, and laboratory data from 167 consecutive secondary infertile men were analyzed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI; categorised 0 vs 1 vs 2 or higher). NCEP-ATP III criteria were used to define MetS. Semen analysis values were assessed based on the 2010 World Health Organization (WHO) reference criteria. Descriptive statistics and logistic regression models tested the association between semen parameters and clinical characteristics and MetS. MetS was found in 20 (12%) of 167 men. Patients with MetS were older (P < 0.001) and had a greater BMI (P < 0.001) compared with those without MetS. MetS patients had lower levels of total testosterone (P = 0.001), sex hormone-binding globulin, inhibin B, and anti-Mόllerian hormone (all P ≤ 0.03), and they were hypogonadal at a higher prevalence (P = 0.01) than patients without MetS. Moreover, MetS patients presented lower values of semen volume, sperm concentration, and sperm normal morphology (all P ≤ 0.03). At multivariate logistic regression analysis, no parameters predicted sperm concentration, normal sperm morphology, and total progressive motility. Our data show that almost 1 of 8 White-European men presenting for secondary couple's infertility is diagnosed with MetS. MetS was found to be associated with a higher prevalence of hypogonadism, decreased semen volume, decreased sperm concentration, and normal morphology in a specific cohort of White-European men.

Serum anti-mullerian hormone and all-cause mortality in men

Several studies have examined an association of anti-mullerian hormone to various risk factors for mortality, however, to the best of our knowledge, no study has reported a direct relationship between anti-mullerian hormone and all-cause mortality. Therefore, we examined the relationship between baseline anti-mullerian hormone levels and subsequent all-cause mortality in men during median follow-up of 9.4 (range = 0-13) years. We used the continuous National Health and Nutrition Examination Surveys from 1999-2004 combined with National Death Index for vital status information through December 2011. Cox proportional hazard models were fit to estimate hazard ratios for all-cause mortality. Models were adjusted for age, ethnic background, body mass index, hypertension, diabetes, smoking status, c-reactive protein, total cholesterol, estimated glomerular filtration rate, serum estradiol, testosterone, sex hormone binding globulin, and androstenedione. Of the 989 men, 30 % were older than 65 years, 51 % were Caucasians, 33 % had hypertension, 27 % were active smokers, and 11 % had diabetes. Mean serum anti-mullerian hormone level of the population was 7.2 (6.3) ng/mL. During the 8943 person-years of follow-up, 164 (17 %) men died. In unadjusted analysis, each unit increase in serum anti-mullerian hormone level was associated with a 13 % lower risk of death (HR = 0.87; 95 %CI = 0.83-0.92). In multivariable models, the inverse association between serum anti-mullerian hormone levels and mortality remained significant (HR = 0.94; 95 %CI = 0.90-0.98) and was independent of confounding variables. Similarly, individuals in the highest quartile had significantly lower risk of death as compared to individuals in the lowest quartile (unadjusted HR = 0.13, 95 %CI = 0.07-0.25; adjusted HR = 0.36, 95 %CI = 0.16-0.81). We found an independent and inverse association between serum anti-mullerian hormone levels and all-cause mortality in men. The mechanism underlying this association is unknown. Further studies are needed to validate our findings in men and to examine this association in women.

Metabolic syndrome in white European men presenting for primary couple's infertility: investigation of the clinical and reproductive burden

Despite complex interactions between obesity, dyslipidemia, hyperinsulinaemia, and the reproductive axis, the impact of metabolic syndrome on human male reproductive function has not been analysed comprehensively. Complete demographic, clinical, and laboratory data from 1337 consecutive primary infertile men were analysed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (categorised 0 vs. 1 vs. 2 or higher). NCEP-ATPIII criteria were used to define metabolic syndrome. Semen analysis values were assessed based on the 2010 World Health Organisation (WHO) reference criteria. Descriptive statistics and logistic regression models tested the association between semen parameters and clinical characteristics and metabolic syndrome. Metabolic syndrome was found in 128 (9.6%) of 1337 men. Patients with metabolic syndrome were older (p < 0.001) and had a greater Charlson Comorbidity Index of 1 or higher (chi-square: 15.6; p < 0.001) compared with those without metabolic syndrome. Metabolic syndrome patients had lower levels of total testosterone (p < 0.001), sex hormone-binding globulin (p = 0.004), inhibin B (p = 0.03), and anti-Müllerian hormone (p = 0.009), and they were hypogonadal at a higher rate (chi-square: 32.0; p < 0.001) than patients without metabolic syndrome. Conversely, the two groups did not differ significantly in further hormonal levels, semen parameters, and rate of either obstructive or non-obstructive azoospermia. At multivariate logistic regression analysis, testicular volume (OR: 0.90; p = 0.002) achieved independent predictor status for WHO pathological semen concentration; conversely, age, Charlson Comorbidity Index scores, metabolic syndrome, and inhibin B values did not. No parameters predicted normal sperm morphology and total progressive motility. Metabolic syndrome accounts for roughly 9% of men presenting for primary couple's infertility. Although metabolic syndrome patients have a lower general male health status, semen analysis values seem independent of the presence of metabolic syndrome.

Determinants of testosterone levels in human male obesity

Testosterone (T) levels are decreased in obese men, but the underlying causes are incompletely understood. Our objective was to explore the relation between low (free) T levels and male obesity, by evaluating metabolic parameters, subcutaneous adipose tissue (SAT) aromatase expression, and parameters of the hypothalamic-pituitary-gonadal axis. We recruited 57 morbidly obese men [33 had type 2 diabetes (DM2)] and 25 normal-weight men undergoing abdominal surgery. Fourteen obese men also attended a follow-up, 2 years after gastric bypass surgery (GBS). Circulating T levels were quantified by LC-MS/MS, whereas free T levels were measured using serum equilibrium dialysis and sex hormone-binding globulin, luteinizing hormone, and follicle-stimulating hormone by immunoassay. SAT biopsies were used to determine adipocyte cell size and aromatase expression by real-time PCR. Total and free T levels were decreased in obese males versus controls, with a further decrease in obese men with DM2 versus obese men without DM2. There were no differences in aromatase expression among the study groups, and sex steroids did not correlate with aromatase expression. Pearson analysis revealed an inverse association between (free) T and SAT cell size, triglycerides, and HOMA-IR. Multivariate analysis confirmed the inverse association between (free) T and SAT cell size (β = -0.321, P = 0.037 and β = -0.441, P = 0.011, respectively), independent of age, triglycerides, HOMA-IR, obesity, or diabetes. T levels were normalized 2 years after GBS. These data suggest that SAT cell size rather than SAT aromatase expression or parameters of the hypothalamic-pituitary-gonadal axis is related to low T in male obesity, which points to adipose cell size-related metabolic changes as a major trigger in decreased T levels.

Gonadal failure is associated with visceral adiposity in myotonic dystrophies

BACKGROUND

Hypogonadism occurs in myotonic dystrophies type 1 (MD1) and type 2 (MD2). Sertoli and Leydig cell secretions, including insulin-like peptide-3 (INSL3), anti-Müllerian hormone (AMH) and inhibin B, were evaluated in male patients with MD.

DESIGN

Academic settings. Forty-four male patients with MD [31 MD1, 13 MD2, aged 59 (50-64) years, median (interquartile range)], age-, sex- and BMI-matched non-MD hypogonadal patients (n = 14) and healthy controls (n = 32). Serum FSH, LH, inhibin B, AMH, testosterone (T) and INSL3 were measured; fat and muscle masses were evaluated by DEXA.

RESULTS

Overt primary hypogonadism occurred in 29% of patients with MD1 and 46% of patients with MD2. Considering subclinical forms, the prevalence increased to 69% of MD1 and 100% of MD2. A half of patients with MD experienced symptoms. INSL3 levels were unaffected in most patients with MD. By contrast, AMH and inhibin B were reduced in most patients with MD and unrelated to age. Patients with MD showed increased body and visceral fat. Free T levels were negatively predicted by fat mass, and AMH and FSH levels were negatively correlated with waist/hip ratio and fat mass. AMH, inhibin B and FSH levels positively correlated with muscle strength and muscle mass.

CONCLUSIONS

AMH and inhibin B secretion failures are common in male patients with MD and are more severe than Leydig cell hormones impairment. AMH and inhibin B measurements might provide clinical utility in evaluating fertility in patients with MD. Serum T, AMH and inhibin B productions are negatively influenced by increased fat mass, while AMH and inhibin B might be markers of muscle impairment.

Body Mass Index Is Associated with Impaired Semen Characteristics and Reduced Levels of Anti-Müllerian Hormone across a Wide Weight Range

There is still controversy as to how body mass index (BMI) affects male reproduction. We investigated how BMI is associated with semen quality and reproductive hormones in 166 men, including 38 severely obese men. Standard semen analysis and sperm DNA integrity analysis were performed, and blood samples were analysed for reproductive hormones. Adjusted for age and time of abstinence, BMI was negatively associated with sperm concentration (B = -0.088, P = 0.009), total sperm count (B = -0.223, P = 0.001), progressive sperm motility (B = -0.675, P = 0.007), normal sperm morphology (B = -0.078, P = 0.001), and percentage of vital spermatozoa (B = -0.006, P = 0.027). A negative relationship was observed between BMI and total testosterone (B = -0.378, P < 0.001), sex hormone binding globulin (B = -0.572, P < 0.001), inhibin B (B = -3.120, P < 0.001) and anti-Müllerian hormone (AMH) (B = -0.009, P < 0.001). Our findings suggest that high BMI is negatively associated with semen characteristics and serum levels of AMH.

Elderly men have low levels of anti-Müllerian hormone and inhibin B, but with high interpersonal variation: a cross-sectional study of the sertoli cell hormones in 615 community-dwelling men

The Sertoli cells of the testes secrete anti-Müllerian hormone (Müllerian inhibiting Substance, AMH) and inhibin B (InhB). AMH triggers the degeneration of the uterine precursor in male embryos, whereas InhB is part of the gonadal-pituitary axis for the regulation of sperm production in adults. However, both hormones are also putative regulators of homeostasis, and age-related changes in these hormones may therefore be important to the health status of elderly men. The levels of AMH in elderly men are unknown, with limited information being available about age-related changes in InhB. We have therefore used ELISAs to measure Sertoli cell hormone levels in 3 cohorts of community-dwelling men in New Zealand. In total, 615 men were examined, 493 of which were aged 65 or older. Serum AMH and InhB levels inversely correlated with age in men older than 50 years (p<0.001) but not in the younger men. A minority of elderly men had undetectable levels of AMH and InhB. The variation in hormone levels between similarly aged men increased with the age of men. AMH and InhB partially correlated with each other as expected (r = 0.48, p<0.001). However, the ratio of the two Sertoli hormones varied significantly between men, with this variation increasing with age. Elderly men selected for the absence of cardiovascular disease had AMH levels similar to those of young men whereas their InhB levels did not differ from aged-matched controls. These data suggests that Sertoli cell number and function changes with age, but with the extent and nature of the changes varying between men.

The complex interaction between obesity, metabolic syndrome and reproductive axis: a narrative review

The aim of this narrative review is to provide current evidence for the interaction between obesity, metabolic syndrome (MS) and reproductive axis. Gonadotropin-releasing hormone (GnRH) pulses and, consequently, normal function of reproductive (hypothalamus-pituitary-gonadal) axis depend on normal energy balance, which presupposes sufficient food intake, reasonable energy consumption and average thermoregulatory costs. In case of an energy imbalance, reproductive dysfunction may occur. In young women, excessive leanness is accompanied by puberty delay, whereas premature puberty might be a manifestation of obesity. In a similar way, obesity in men affects fertility. Excess adipose tissue results in increased conversion of testosterone to estradiol, which may lead to secondary hypogonadism through reproductive axis suppression. Moreover, oxidative stress at the level of the testicular micro-environment may result in decreased spermatogenesis and sperm damage. Products of the adipocyte, such as leptin, adiponectin and resistin, and gut peptides, such as ghrelin, are considered to be crucial in the interaction between energy balance and reproduction. Finally, an indirect evidence for the interplay between MS and reproductive axis is the fact that when treating components of one, parameters of the other can be improved as well. These therapeutic interventions include lifestyle modifications, pharmacological agents, such as sex hormone replacement therapy, and surgical procedures. Although many issues remain unclear, the elucidation of the complex interaction between MS and reproductive axis will have obvious clinical implications in the therapeutic approach of both entities.

Metabolic regulation is important for spermatogenesis

Male factor infertility is increasing in developed countries, and several factors linked to lifestyle have been shown to negatively affect spermatogenesis. Sertoli cells are pivotal to spermatogenesis, providing nutritional support to germ cells throughout their development. Sertoli cells display atypical features in their cellular metabolism; they can metabolize various substrates, preferentially glucose, the majority of which is converted to lactate and not oxidized via the tricarboxylic acid cycle. Why Sertoli cells preferentially export lactate for germ cells is not entirely understood. However, lactate is utilized as the main energy substrate by developing germ cells and has an antiapoptotic effect on these cells. Several biochemical mechanisms contribute to the modulation of lactate secretion by Sertoli cells. These include the transport of glucose through the plasma membrane, mediated by glucose transporters; the interconversion of pyruvate to lactate by lactate dehydrogenase; and the release of lactate mediated by monocarboxylate transporters. Several factors that modulate Sertoli cell metabolism have been identified, including sex steroid hormones, which are crucial for maintenance of energy homeostasis, influencing the metabolic balance of the whole body. In fact, energy status is essential for normal reproductive function, since the reproductive axis has the capacity to respond to metabolic cues.