Human chorionic gonadotropin stimulation gives evidence of differences in testicular steroidogenesis in Klinefelter syndrome, as assessed by liquid chromatography-tandem mass spectrometry

Intratesticular Testosterone and Its Precursors among Azoospermic Men: A Pilot Study

PURPOSE

The study aimed to comprehensively analyze testosterone and precursor concentrations in the testicular interstitial fluid (TIF) of men with azoospermia, exploring their significance in the testicular microenvironment and their correlation with testicular sperm retrieval outcomes.

MATERIALS AND METHODS

We analyzed 37 TIF samples, including 5 from men with obstructive azoospermia (OA) and 32 from men with non-obstructive azoospermia (NOA). Liquid chromatography with tandem mass spectrometry quantified testosterone and precursor levels. Comparative assessments of the outcomes of testicular sperm retrieval were performed between the OA and NOA groups as well as among men with NOA.

RESULTS

Men with NOA who had not undergone hormone treatment exhibited significantly higher intratesticular concentrations of testosterone (median 1,528.1 vs. 207.5 ng/mL), androstenedione (median 10.6 vs. 1.9 ng/mL), and 17-OH progesterone (median 13.0 vs. 1.8 ng/mL) than men diagnosed with OA. Notably, in the subgroup of patients with NOA subjected to medical treatment, men with successful sperm retrieval had significantly reduced levels of androstenedione (median androstenedione 5.7 vs. 18.5 ng/mL, p=0.004). Upon a more detailed analysis of these men who underwent hormone manipulation treatment, the testosterone/androstenedione ratio (indicative of HSD17B3 enzyme activity) was markedly increased in men with successful sperm retrieval (median: 365.8 vs. 165.0, p=0.008) compared with individuals with NOA who had unsuccessful sperm recovery. Furthermore, within the subset of men with NOA who did not undergo medical treatment before microdissection testicular sperm extraction but achieved successful sperm retrieval, the ratio of 17-OH progesterone/progesterone (indicative of CYP17A1 activity) was substantially higher.

CONCLUSIONS

The study suggests distinct testosterone biosynthesis pathways in men with compromised spermatogenesis and those with normal spermatogenesis. Among NOA men with successful retrieval after hormone optimization therapy, there was decreased androstenedione and increased HSD17B3 enzyme activity. These findings have diagnostic and therapeutic implications for the future.

Testicular Microvascular Flow Is Altered in Klinefelter Syndrome and Predicts Circulating Testosterone

CONTEXT

Experimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS.

OBJECTIVE

To analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function.

DESIGN AND SETTING

Prospective study. University setting.

PATIENTS

Sixty-eight testicular scans, 34 testes from 19 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (control) who underwent CEUS for incidental nonpalpable testicular lesions.

MAIN OUTCOMES

CEUS kinetic parameters.

RESULTS

CEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched controls. Specifically, the wash-in time (P = 0.018), mean transit time (P = 0.035), time to peak (P < 0.001), and wash-out time (P = 0.004) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings and supported a role for reduced venous blood flow as independent predictor of total T levels.

CONCLUSIONS

Testicular venous blood flow is altered in KS and independently predicts T peripheral release.

Review on Bee Products as Potential Protective and Therapeutic Agents in Male Reproductive Impairment

Bee products are sources of functional food that have been used in complementary medicine to treat a variety of acute and chronic illnesses in many parts of the world. The products vary from location to location as well as country to country. Therefore, the aim of this review was to identify various bee products with potential preventive and therapeutic values used in the treatment of male reproductive impairment. We undertook a vigorous search for bee products with preventive and therapeutic values for the male reproductive system. These products included honey, royal jelly, bee pollen, bee brood, apilarnil, bee bread, bee wax, and bee venom. We also explained the mechanisms involved in testicular steroidogenesis, reactive oxygen species, oxidative stress, inflammation, and apoptosis, which may cumulatively lead to male reproductive impairment. The effects of bee pollen, bee venom, honey, propolis, royal jelly, and bee bread on male reproductive parameters were examined. Conclusively, these bee products showed positive effects on the steroidogenic, spermatogenic, oxidative stress, inflammatory, and apoptotic parameters, thereby making them a promising possible preventive and therapeutic treatment of male sub/infertility.

How Successful Is Surgical Sperm Retrieval in Klinefelter Syndrome?

Klinefelter Syndrome (KS) is characterized by the presence of an extra X chromosome. It was first diagnosed in 1942 in a group of azoospermic men. KS is the most common chromosomal abnormality encountered in infertile men and accounts for more than 10% of the causes of azoospermia. Men who are azoospermic may still father children via testicular sperm extraction followed by intracytoplasmic sperm injection (ICSI). This review article summarizes the success rates of the available techniques for surgical sperm retrieval (SSR) in KS including conventional testicular sperm extraction (cTESE) and micro testicular sperm extraction (mTESE), as well as the risks of these procedures for future fertility. The evidence indicates that the SSR rate is as successful in non-mosaic men with KS as those with normal karyotypes, with retrieval rates of up to 55% reported. The influence of different factors that affect the chances of a successful outcome are discussed. In particular, the impact of aneuploidy rate, physical characteristics, co-morbidities, reproductive endocrine balance and the use of different hormone management therapies are highlighted. Evidence is presented to suggest that the single most significant determinant for successful SSR is the age of the patient. The success of SSR is also influenced by surgical technique and operative time, as well as the skills of the surgeon and embryology team. Rescue mTESE may be used successfully following failed TESE in KS patients in combination with hormone stimulation.

Testicular Involvement is a Hallmark of Apo A-I Leu75Pro Mutation Amyloidosis

CONTEXT

Apo A-I Leu75Pro is a rare hereditary form of amyloidosis that mainly involves the kidney, the liver, and the testis.

OBJECTIVE

To define the characteristics of organ damage and testis impairment in the largest cohort collected to date of men with Apo A-I Leu75Pro amyloidosis.

DESIGN, SETTING, AND PATIENTS

Retrospective study from a prospectively collected database of 129 male subjects >18 years with Apo A-I Leu75Pro amyloidosis from a reference center at the University Hospital of Brescia, Italy.

MAIN OUTCOME MEASURES

We evaluated liver and renal function, scrotal ultrasound, reproductive hormone levels, testis biopsy, hypogonadal symptoms, and fertility.

RESULTS

Progressive involvement of testis, kidney, and liver was observed in 96/129 (74.4%) cases. Testis impairment was found in 88/129 patients (68.2%), liver in 59 (45.7%) and renal in 50 (38.8%). Testis damage was often the first manifestation of the disease and the only dysfunction in 30% of younger patients (<38 years). Testicular involvement was characterized mainly by primary (73/88 patients, 83.0%) and subclinical (8/88, 9.1%) hypogonadism. Almost all (85/88, 96.6%) also had high follicle-stimulating hormone, suggesting a primary global damage of endocrine and spermatogenic functions, and 30% of them did not conceive. Macroorchidism was found in 53/88 (60.2%) patients, especially in men <54 years (30/33, 90.9%). Apo A-I amyloid deposits were found in Sertoli cells, germinal epithelium, and vessel walls.

CONCLUSION

In men with Apo A-I Leu75Pro amyloidosis, testicular involvement is the hallmark of the disease, characterized by global primary testicular dysfunction and macroorchidism due to amyloid deposits.

Testicular blood supply is altered in the 41,XXY* Klinefelter syndrome mouse model

Hypergonadotropic hypogonadism is a major feature of Klinefelter syndrome (KS), assumed to be caused by testicular hormone resistance. It was previously shown that intratesticular testosterone levels in vivo and Leydig cell function in vitro seem to be normal indicating other functional constraints. We hypothesized that impaired testicular vascularization/blood flow could be a co-factor to the observed hypergonadotropic hypogonadism. We evaluated the testicular vascular system by measuring blood vessel sizes during postnatal development and testis blood flow in adult 41,XX^Y* mice. Proportional distribution and size of blood vessels were analyzed during testicular development (1, 3, 5, 7, 10, 21 dpp, 15 wpp). While ratios of the vessel/testis area were different at 15 wpp only, a lower number of smaller and mid-sized blood vessels were detected in adult KS mice. For testicular blood flow determination we applied contrast enhanced ultrasound. Floating and reperfusion time for testicular blood flow was increased in 41,XX^Y* mice (floating: XY* 28.8 ± 1.69 s vs XX^Y* 44.6 ± 5.6 s, p = 0.0192; reperfusion XY* 19.7 ± 2.8 s vs XX^Y*: 29.9 ± 6.2 s, p = 0.0134), indicating a diminished blood supply. Our data strengthen the concept that an impaired vascularization either in conjunction or as a result of altered KS testicular architecture contributes to hormone resistance.

Role of treatment with human chorionic gonadotropin and clinical parameters on testicular sperm recovery with microdissection testicular sperm extraction and intracytoplasmic sperm injection outcomes in 184 Klinefelter syndrome patients

OBJECTIVE

To investigate whether preoperative human chorionic gonadotropin (hCG) treatment can help predict the outcomes of microdissection testicular sperm extraction (micro-TESE) and affect fertility outcomes in non-mosaic Klinefelter syndrome (KS) patients.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated fertility center.

PATIENT(S)

A total of 184 non-mosaic KS patients who underwent micro-TESE with or without preoperative hCG treatment from January 2016 to July 2019.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Sperm retrieval rate (SRR) with and without hCG treatment, logistic models analysis.

RESULT(S)

Eighty KS patients (43.5%) had successful sperm retrievals after micro-TESE. There was no statistically significant difference in the SRR between the group who received hCG treatment and the group that did not (44.0% vs. 43.3%). Logistic regression analyses demonstrated that the hCG treatment had no statistically significant effect on successful sperm retrieval. However, higher preoperative testosterone (T) levels seemed to be associated with a higher probability of successful sperm retrieval (multivariate adjusted odds ratio 1.09; 95% confidence interval [CI], 1.04-1.16). The prediction model for SRR on KS patients had an area under the curve of 67.3% (95% CI, 59.3-75.3%). In the hCG treatment group, the data indicated that the three parameters of testicular volume, pretreatment T level, and alterations of T were associated with the probability of successful sperm retrieval. Moreover, hCG therapy did not affect intracytoplasmic sperm injection (ICSI) outcomes. No differences in the pregnancy rate or live-birth rate were observed between the two groups.

CONCLUSION(S)

Therapy with hCG does not affect SRR or ICSI outcomes of non-mosaic KS patients. However, preoperative T levels, whether treated with hCG or not, can predict the chance of sperm retrieval with micro-TESE.

Effects of acute hCG stimulation on serum INSL3 and 25-OH vitamin D in Klinefelter syndrome

BACKGROUND

It has recently been suggested that the hypergonadotropic hypogonadism characterizing Klinefelter syndrome (KS) might not be due to a steroidogenic dysfunction per se, but mainly to an altered testosterone (T) secretion into the bloodstream. However, the Leydig cell functionality remains incompletely studied in KS, and new markers should be considered. Previous data indicated that chronic hCG stimulation influences the production of both insulin-like peptide 3 (INSL3) and 25-hydroxy-vitamin D (25-VD) in eugonadal men.

AIM OF THE STUDY

To evaluate INSL3 and 25-VD serum levels, as markers of Leydig cell functionality, in association with sex steroids, after an acute hCG test in a group of KS patients and healthy volunteers.

METHODS

A retrospective analysis of a prospective case-control clinical trial was carried out. KS patients (n = 11) and age-matched healthy controls (n = 11) provided a basal blood sample (V0) immediately followed by a single intramuscular injection of hCG 5000 IU. Blood samples were taken in the following five days (V1-V5).

RESULTS

At baseline, INSL3 was lower in KS patients compared with controls (P = .007). When adjusted for INSL3 levels, the production of steroids was similar between KS patients and controls. 25-VD was in the insufficient range both in KS patients and in controls and was not different (P = .064). Acute hCG stimulation increased neither INSL3 nor 25-VD in both KS patients and controls. In controls, an inverse correlation was detected between INSL3 levels and body mass index (P = .020) and waist circumference (P = .020).

CONCLUSIONS

INSL3 secretion is independent from steroidogenesis, and its production is mostly not influenced by acute hCG stimulation both in KS men and in controls. INSL3 serum levels should be considered as a marker of Leydig cell differentiation and numbers rather than steroidogenesis. 25-VD serum levels are also not increased by a single acute hCG administration, which was not able to restore the normal concentrations of 25-VD.

Fertility in Adolescents With Klinefelter Syndrome: A Survey of Current Clinical Practice

CONTEXT

Progress has been made in determining the fertility timeline and potential in adolescents with Klinefelter syndrome; however, medical professionals are currently without protocols to guide treatment.

OBJECTIVE

To evaluate the current practices regarding fertility and andrology care in adolescent males with Klinefelter syndrome.

DESIGN

A 24-question survey was developed to elicit practitioner background/expertise and management practices. This was distributed to members of the Society for the Study of Male Reproduction, the Pediatric Endocrine Society, and the Endocrine Society.

SETTING

N/A.

PATIENTS

Adolescent males with Klinefelter syndrome.

INTERVENTION

None.

MAIN OUTCOME MEASURED

Current practices regarding fertility and andrology care.

RESULTS

232 responses were received from 133 (57%) adult endocrinologists, 60 (26%) pediatric endocrinologists, and 39 (17%) urologists. Among these, 69% of respondents were in academics, 62% practiced for > 10 years, and 65% received formal training in Klinefelter syndrome. All specialties encouraged sperm banking in late puberty, however most disagreed with the practice in early puberty. Seventy-eight percent agreed that testicular biopsy should be offered if no sperm was found in the ejaculate. The perceived optimal age for testicular biopsy varied among specialists. Clinical symptoms of hypogonadism (28%), rising gonadotropin levels (15%), and testosterone levels (15%) were the most commonly cited reasons for initiation of testosterone replacement therapy.

CONCLUSION

Fertility preservation practices in adolescents with Klinefelter syndrome vary greatly within and among the specialties caring for these patients. These findings should guide future research and highlight the importance of establishing clinical practice guidelines.

Relative hyperestrogenism in Klinefelter Syndrome: results from a meta-analysis

OBJECTIVE

Klinefelter Syndrome (KS) is classically described as characterized by hyperestrogenism, although solid evidence is lacking. This study aims to test the hypothesis that men with KS have higher serum estradiol than normal controls.

DESIGN

Meta-analysis of all studies extracted by MEDLINE from 1942 to 31 January 2018. All studies reporting serum estradiol measurement were considered, among them only case-control studies were included in the meta-analysis.

METHODS

Meta-analysis was conducted according to the PRISMA statement using RevMan.

RESULTS

Out of 4120 articles, 23 case-control studies, 14 case series, and 19 case reports reported data on serum estradiol. A total of 707 KS and 1019 controls were included in the meta-analysis. Serum estradiol was slightly, but significantly higher in KS than controls (mean difference 4.25 pg/mL; CI: 0.41, 8.10 pg/mL; p = 0.030). This difference was lost considering only studies using estradiol assays with good accuracy (5.48 pg/mL, CI: -2.11, 13.07 pg/mL; p = 0.160). Serum testosterone and estradiol/testosterone ratio were significantly lower and higher in KS than controls, respectively. Data from KS case series and case reports confirmed that serum estradiol is within the normal ranges.

CONCLUSIONS

Serum estradiol is not increased in KS although slightly higher than controls. However, the meta-analysis that included only studies using a serum estradiol assay with good accuracy showed no difference in serum estradiol between KS and controls. The traditional belief that KS is associated with elevated serum estradiol should be reconsidered. This meta-analysis shows that men with KS have relative hyperestrogenism (increased estradiol/testosterone ratio) compared to controls.

Probing the Effect of Sildenafil on Progesterone and Testosterone Production by an Intracellular FRET/BRET Combined Approach

Forster resonance energy transfer (FRET)-based biosensors have been recently applied to the study of biological pathways. In this study, a new biosensor was validated for the first time in live HEK293 and steroidogenic MLTC-1 cell lines for studying the effect of the PDE5 inhibitor on the hCG/LH-induced steroidogenic pathway. The sensor improves FRET between a donor (D), the fluorescein-like diarsenical probe that can covalently bind a tetracysteine motif fused to the PDE5 catalytic domain, and an acceptor (A), the rhodamine probe conjugated to the pseudosubstrate cGMPS. Affinity constant ( K_d) values of 5.6 ± 3.2 and 13.7 ± 0.8 μM were obtained with HEK293 and MLTC-1 cells, respectively. The detection was based on the competitive displacement of the cGMPS-rhodamine conjugate by sildenafil; the K_i values were 3.6 ± 0.3 nM (IC₅₀ = 2.3 nM) in HEK293 cells and 10 ± 1.0 nM (IC₅₀ = 3.9 nM) in MLTC-1 cells. The monitoring of both cAMP and cGMP by bioluminescence resonance energy transfer allowed the exploitation of the effects of PDE5i on steroidogenesis, indicating that sildenafil enhanced the gonadotropin-induced progesterone-to-testosterone conversion in a cAMP-independent manner.

Klinefelter syndrome, insulin resistance, metabolic syndrome, and diabetes: review of literature and clinical perspectives

PURPOSE

Klinefelter syndrome (KS), the most frequent chromosomic abnormality in males, is associated with hypergonadotropic hypogonadism and an increased risk of cardiovascular diseases (CVD). The mechanisms involved in increasing risk of cardiovascular morbidity and mortality are not completely understood. This review summarises the current understandings of the complex relationship between KS, metabolic syndrome and cardiovascular risk in order to plan future studies and improve current strategies to reduce mortality in this high-risk population.

METHODS

We searched PubMed, Web of Science, and Scopus for manuscripts published prior to November 2017 using key words "Klinefelter syndrome" AND "insulin resistance" OR "metabolic syndrome" OR "diabetes mellitus" OR "cardiovascular disease" OR "testosterone". Manuscripts were collated, studied and carried forward for discussion where appropriate.

RESULTS

Insulin resistance, metabolic syndrome, and type 2 diabetes are more frequently diagnosed in KS than in the general population; however, the contribution of hypogonadism to metabolic derangement is highly controversial. Whether this dangerous combination of risk factors fully explains the CVD burden of KS patients remains unclear. In addition, testosterone replacement therapy only exerts a marginal action on the CVD system.

CONCLUSION

Since fat accumulation and distribution seem to play a relevant role in triggering metabolic abnormalities, an early diagnosis and a tailored intervention strategy with drugs aimed at targeting excessive visceral fat deposition appear necessary in patients with KS.

MECHANISMS IN ENDOCRINOLOGY: The sexually dimorphic role of androgens in human metabolic disease

Female androgen excess and male androgen deficiency manifest with an overlapping adverse metabolic phenotype, including abdominal obesity, insulin resistance, type 2 diabetes mellitus, non-alcoholic fatty liver disease and an increased risk of cardiovascular disease. Here, we review the impact of androgens on metabolic target tissues in an attempt to unravel the complex mechanistic links with metabolic dysfunction; we also evaluate clinical studies examining the associations between metabolic disease and disorders of androgen metabolism in men and women. We conceptualise that an equilibrium between androgen effects on adipose tissue and skeletal muscle underpins the metabolic phenotype observed in female androgen excess and male androgen deficiency. Androgens induce adipose tissue dysfunction, with effects on lipid metabolism, insulin resistance and fat mass expansion, while anabolic effects on skeletal muscle may confer metabolic benefits. We hypothesise that serum androgen concentrations observed in female androgen excess and male hypogonadism are metabolically disadvantageous, promoting adipose and liver lipid accumulation, central fat mass expansion and insulin resistance.

The steroid response to human chorionic gonadotropin (hCG) stimulation in men with Klinefelter syndrome does not change using immunoassay or mass spectrometry

PURPOSE

Liquid-chromatography tandem mass-spectrometry (LC-MS/MS) was developed in parallel to Immunoassays (IAs) and today is proposed as the "gold standard" for steroid assays. Leydig cells of men with Klinefelter syndrome (KS) are able to respond to human chorionic gonadotropin (hCG) stimulation, even if testosterone (T) production was impaired. The aim was to evaluate how results obtained by IAs and LC-MS/MS can differently impact on the outcome of a clinical research on gonadal steroidogenesis after hCG stimulation.

METHODS

A longitudinal, prospective, case-control clinical trial. (clinicaltrial.gov NCT02788136) was carried out, enrolling KS men and healthy age-matched controls, stimulated by hCG administration. Serum steroids were evaluated at baseline and for 5 days after intramuscular injection of 5000 IU hCG using both IAs and LC-MS/MS.

RESULTS

13 KS patients (36 ± 9 years) not receiving T replacement therapy and 14 controls (32 ± 8 years) were enrolled. T, progesterone, cortisol, 17-hydroxy-progesterone (17OHP) and androstenedione, were significantly higher using IAs than LC-MS/MS. IAs and LC-MS/MS showed direct correlation for all five steroids, although the constant overestimation detected by IAs. Either methodology found the same 17OHP and T increasing profile after hCG stimulation, with equal areas under the curves (AUCs).

CONCLUSIONS

Although a linearity between IA and LC-MS/MS is demonstrated, LC-MS/MS is more sensitive and accurate, whereas IA shows a constant overestimation of sex steroid levels. This result suggests the need of reference intervals built on the specific assay. This fundamental difference between these two methodologies opens a deep reconsideration of what is needed to improve the accuracy of steroid hormone assays.

Dynamic GnRH and hCG testing: establishment of new diagnostic reference levels

OBJECTIVE

Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) stimulation tests may be used to evaluate the pituitary and testicular capacity. Our aim was to evaluate changes in follicular-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone after GnRH and hCG stimulation in healthy men and assess the impact of six single nucleotide polymorphisms on the responses.

DESIGN

GnRH and hCG stimulation tests were performed on 77 healthy men, 18-40 years (reference group) at a specialized andrology referral center at a university hospital. The potential influence of the tests was illustrated by results from 45 patients suspected of disordered hypothalamic-pituitary-gonadal axis.

METHODS

Baseline, stimulated, relative and absolute changes in serum FSH and LH were determined by ultrasensitive TRIFMA, and testosterone was determined by LC-MS/MS.

RESULTS

For the reference group, LH and FSH increased almost 400% and 40% during GnRH testing, stimulated levels varied from 4.4 to 58.8 U/L and 0.2 to 11.8 U/L and FSH decreased in nine men. Testosterone increased approximately 110% (range: 18.7-67.6 nmol/L) during hCG testing. None of the polymorphisms had any major impact on the test results. Results from GnRH and hCG tests in patients compared with the reference group showed that the stimulated level and absolute increase in LH showed superior identification of patients compared with the relative increase, and the absolute change in testosterone was superior in identifying men with Leydig cell insufficiency, compared with the relative increase.

CONCLUSIONS

We provide novel reference ranges for GnRH and hCG test in healthy men, which allows future diagnostic evaluation of hypothalamic-pituitary-gonadal disorders in men.