A. Di Mambro

Spermatogenesis in Klinefelter syndrome

Background: Klinefelter syndrome (KS) (47,XXY) is the most common sex chromosomal disorder, and it is a frequent form of male hypogonadism and infertility. Although the majority of these patients are azoospermic, they might have severe oligozoospermia or residual single-residual foci with spermatogenesis in the testis. Aim: We report our experience on sperm retrieval in the ejaculate and testis, and evaluate the frequency of chromosome abnormalities in sperm of KS. Subjects and methods: Eighty-four 47,XXY KS were evaluated with seminal analysis, body hair distribution, reproductive hormones, ultrasonographic scanning of the testis and prostate, bilateral testicular sperm extraction (TESE), sperm or testicular cells sex chromosomes aneuploidies. Results: Out of 84 patients, 7 (7/84; 8.3%) had sperm in the ejaculate. Out of the 77 azoospermic patients, 24 underwent TESE and 9 (9/24; 37.5%) had successful sperm recovery. The comparison of reproductive hormones, age and testicular volume did not show significant differencesbetween patients with and without successful sperm recovery in semen or TESE. Patients without successful sperm recovery in semen analysis or TESE had signs of hypoandrogenism more evident than patients with successful sperm recovery. Patients with KS produced a higher number of sperm aneuploidy with respect to normozoospermic fertile controls and non-genetic severely oligozoospermic men. Conclusions: Men with KS are not always sterile. In some of these patients sperm can be found in semen or in the testis, but the proportion of sperm aneuploidy is high. Signs of hypoandrogenism seem to be associated with low sperm recovery rate.

Osteoporosis in Klinefelter's syndrome

Hypogonadism represents one of the most important causes of male osteoporosis. Testosterone regulates male bone metabolism both indirectly by aromatization to estrogens and directly through the androgen receptor (AR) on osteoblasts, promoting periosteal bone formation during puberty and reducing bone resorption during adult life. Early onset of testosterone deficiency, as observed in Klinefelters syndrome (KS), is an important risk factor for precocious osteoporosis. Osteoporosis is present in up to 40% of subjects with KS and has usually been attributed to low testosterone levels. However, reduced bone mass might be present also in KS men with normal testosterone levels and testosterone replacement therapy does not always restore bone density in KS patients. Possible new determinants for osteoporosis in KS might be related to the AR function and insulin-like factor 3 (INSL3) levels. The CAG length and inactivation pattern of the AR in KS have been related to osteoporosis, but definitive proof is lacking. INSL3 has an anabolic role on bone metabolism by acting on osteoblasts and INSL3 levels are low in KS. Therefore, low INSL3 concentrations might represent a possible new pathogenic mechanism for reduced bone mass in KS.

Endothelial progenitor cells as a new cardiovascular risk factor in Klinefelter's syndrome

Klinefelter syndrome (KS) is associated with a significant reduced life expectancy (2.1 years) including greater mortality from cardiovascular diseases. Underlying causes that may involve low levels of testosterone as well as the extra X chromosome are not fully understood. Low testosterone may have a direct affect on vascular tissue or act indirectly via metabolic effects. Testosterone levels may act genomically on cardiac function via the androgen receptor (AR) or non-genomically. Recently, it has been demonstrated that a reduced number of circulating endothelial progenitor cells (EPCs) is an independent predictor of morbidity and mortality from cardiovascular diseases. Because EPCs have never been studied in KS, we evaluated the number of circulating EPCs in 68 adult 47,XXY Klinefelter men and 46 healthy males. Patients and controls were divided into two groups, according to the absence or presence of cardiovascular risk factors (CRFs). Controls without CRFs had significantly higher levels of EPCs than controls with CRFs; on the contrary, KS patients without CRFs had EPCs levels similar to KS men with risk factors and significantly lower with respect to controls without CRFs. The number of EPCs in patients with hypogonadism was not different from that of those with normal testosterone levels. Twenty-two hypogonadal patients were re-evaluated after 6 months of androgen therapy, but we did not observe any modification in the number of EPCs. These primary hypothesis-generating data suggest that factors involved in KS, whether hypogonadism, CRFs or other genetically determined factors related to the supernumerary X chromosome might contribute to a reduction in EPCs number and that this could be considered another CRF contributing to the increased mortality of these subjects.

Altered bone status in unilateral testicular cancer survivors: Role of CYP2R1 and its luteinizing hormone-dependency

Background: Recent data suggest a potential role of testis in vitamin D activation, where Leydig cells could represent key players in this process since they express the highest amount of CYP2R1, a key enzyme involved in vitamin D 25 hydroxylation. Aim: To evaluate bone status in unilateral orchiectomy and to assess in vivo and in vitro LH-dependency of Vitamin D 25 hydroxylation. Subjects and methods: 125 normotestosteronemic patients with testicular cancer (TC), featured by unilateral orchiectomy and 41 age-matched healthy male controls were studied in the Center for Human Reproduction Pathology at the University of Padova. To evaluate LH-dependency of Vitamin D 25 hydroxylation in vitro, Leydig cell cultures were stimulated with hCG and assessed for CYP2R1 expression, whereas in vivo 10 hypogonadotropic hypogonadal (HH) patients were evaluated before and after treatment with gonadotropins for bone metabolism markers. Hormonal pattern and bone metabolism markers were measured in all subjects, whereas 105 patients and 41 controls underwent bone densitometry by DEXA. Results: In TC patients 25-hydroxyvitamin D levels were significantly lower compared to controls. Furthermore, 23.8% of patients with TC displayed low bone density (Z-score <−2 SD). None of the 41 control subjects showed any significant alteration of BMD. In vitro and in vivo studies revealed that CYP2R1 expression in Leydig cells appeared to be hCG dependent. Conclusion: Our data show an association between TC and alteration of the bone status, despite unvaried androgen and estrogen levels, suggesting the evaluation of bone status and possible vitamin D deficiency in TC survivors.

The Klinefelter syndrome is associated with high recurrence of copy number variations on the X chromosome with a potential role in the clinical phenotype

The Klinefelter syndrome (KS) is the most frequent sex chromosomal disorder in males, characterized by at least one supernumerary X chromosome (most frequent karyotype 47,XXY). This syndrome presents with a broad range of phenotypes. The common characteristics include small testes and infertility, but KS subjects are at increased risk of hypogonadism, cognitive dysfunction, obesity, diabetes, metabolic syndrome, osteoporosis, and autoimmune disorders, which are present in variable proportion. Although part of the clinical variability might be linked to a different degree of testicular function observed in KS patients, genetic mechanisms of the supernumerary X chromosome might contribute. Gene‐dosage effects and parental origin of the supernumerary X chromosome have been suggested to this regard. No study has been performed analyzing the genetic constitution of the X chromosome in terms of copy number variations (CNVs) and their possible involvement in phenotype of KS. To this aim, we performed a SNP arrays analysis on 94 KS and 85 controls. We found that KS subjects have more frequently than controls X‐linked CNVs (39/94, [41.5%] with respect to 12/42, [28.6%] of females, and 8/43, [18.6%] of males, p < 0.01). The number of X‐linked CNVs in KS patients was 4.58 ± 1.92 CNVs/subject, significantly higher with respect to that found in control females (1.50 ± 1.29 CNVs/subject) and males (1.14 ± 0.37 CNVs/subject). Importantly, 94.4% X‐linked CNVs in KS subjects were duplications, higher with respect to control males (50.0%, p < 0.001) and females (83.3%, p = 0.1). Half of the X‐linked CNVs fell within regions encompassing genes and most of them (90%) included genes escaping X‐inactivation in the regions of X–Y homology, particularly in the pseudoautosomal region 1 (PAR1) and Xq21.31. This study described for the first time the genetic properties of the X chromosome in KS and suggests that X‐linked CNVs (especially duplications) might contribute to the clinical phenotype.

Increased osteocalcin-positive endothelial progenitor cells in hypogonadal male patients

Objective: Endothelial dysfunction is considered a key factor in the development of cardiovascular diseases. Endothelial regeneration is necessary for the maintenance of endothelial function and circulating endothelial progenitor cells (EPC) participate of it in both direct and indirect manner. The molecular phenotype of EPC is not univocally defined and recent studies identified an osteocalcin (OCN)-positive (EPC-OCN+) subpopulation of EPC highly correlated with atherosclerosis progression. Aim: Considering that hypogonadism is a risk factor for cardiovascular diseases and atherosclerosis, we investigated the circulating levels of EPC-OCN+ in hypogonadal patients. Subjects and methods: Ten hypogonadotropic hypogonadal (HH) male patients and 30 healthy eugonadal men were evaluated for clinical status and hormonal levels. Circulating levels of CD34+/CD133+/kinase insert domain-receptor+ EPC and EPC-OCN+ were also determined by flow cytometry. Results: Compared to controls, HH patients displayed lower FSH, LH, estradiol, testosterone, and EPC levels. On the contrary, EPC-OCN + were significantly increased. Conclusions: The observed association of low levels of circulating EPC and increased values of EPC-OCN+ sub-population in hypogonadal men strengthens the significance of hypogonadism as cardiovascular risk factor.

Prostate volume and growth during testosterone replacement therapy is related to visceral obesity in Klinefelter syndrome

OBJECTIVE Klinefelter syndrome (KS) is a chromosomal alteration characterized by increased risk of metabolic syndrome, mainly caused by visceral obesity. In the last years, obesity has been studied as a potential risk factor for prostate disease and recently a link has been demonstrated between visceral adiposity with prostate volume. The aim of this study was to analyze the relationship between obesity and prostate volume and growth during testosterone therapy in KS subjects. DESIGN AND METHODS We evaluated reproductive hormones, metabolic parameters, anthropometric measures, PSA, and prostate volume in 121 naïve non-mosaic KS patients and 60 age-matched healthy male controls. Fifty-six KS hypogonadic subjects were treated with testosterone-gel 2% and reevaluated after 18 months of treatment. RESULTS Prostate volume in KS was positively related to waist circumference (WC). The KS group with WC ≥94 cm had significantly higher prostate volume, BMI, insulin plasma levels, homeostasis model assessment index, total cholesterol, triglycerides, and glycemia with respect to the KS group with WC <94 cm. After testosterone replacement therapy, only hypogonadic KS men with WC ≥94 cm had a statistically significant increase in prostate volume. Furthermore, in untreated KS subjects, prostate volume showed a statistically significant increase after 18 months of follow-up only in subjects with WC ≥94 cm. CONCLUSIONS This study showed that visceral obesity, insulin resistance, and lipid and glucose metabolism alterations are associated with prostate volume and growth during testosterone replacement therapy in KS, independently from androgen or estrogen levels. These latter findings might provide the basis for a better management and follow-up of KS subjects.

Endocrine and psychological aspects of sexual dysfunction in Klinefelter patients

Klinefelter syndrome is a frequent cause of hypogonadism, but despite hundreds of publications on different aspects of Klinefelter syndrome, only a few studies dealt with sexual dysfunction. In particular, testosterone is critical for various aspects of sexual response, but its role on sexuality in Klinefelter syndrome patients is debatable and no studies have evaluated the efficacy of testosterone treatment on sexual dysfunction in these subjects. Furthermore, the impact of psychological and relational aspects on sexual function of Klinefelter syndrome subjects is poorly defined. In this study, we aimed to determine the presence and type of sexual dysfunctions in Klinefelter syndrome subjects; to correlate them with testosterone levels and psychosexological and relational domains; and to evaluate the effects of testosterone therapy. We studied 62 non‐mosaic naïve Klinefelter syndrome patients and 60 age‐matched controls by means of medical history, psychosexological history, 15‐item International Index of Erectile Function questionnaire, endocrine assessment, and dynamic penile color Doppler ultrasound. Twenty‐five hypogonadal Klinefelter syndrome patients were studied after 6 months of testosterone replacement therapy. Klinefelter syndrome subjects have reduced 15‐item International Index of Erectile Function scores regarding sexual desire, intercourse satisfaction, and overall satisfaction with respect to controls, and these aspects were significantly associated with testosterone levels. Klinefelter syndrome subjects had also higher prevalence of erectile dysfunction, but no relation with testosterone levels was evident. A high prevalence of a range of psychological disturbances was present in Klinefelter syndrome subjects with erectile dysfunction with respect to those without erectile dysfunction. No statistical difference in the prevalence of premature and delayed ejaculation was observed between Klinefelter syndrome and control subjects. Testosterone replacement therapy improved sexual desire, intercourse satisfaction, and overall satisfaction scores, but had no effect on erectile function. Penile color Doppler ultrasound was normal in all subjects. This study shows that sexual dysfunction in Klinefelter syndrome is multifactorial and related only in part to hypogonadism and largely to psychological disturbances. Evaluation and therapy of sexual dysfunction should include a combined andrological and psychosexological approach.