Klinefelter syndrome and fertility-Impact of X-chromosomal inheritance on spermatogenesis

Morphometric and immunohistochemical analysis as a method to identify undifferentiated spermatogonial cells in adult subjects with Klinefelter syndrome: a cohort study

OBJECTIVE

To study the prevalence of spermatogonia in adult subjects with Klinefelter syndrome (KS) using MAGE-A4 and UCHL1 (PGP9.5) immunohistochemistry as markers for undifferentiated spermatogonial cells. We aimed to compare this method to the gold standard of hematoxylin and eosin (H & E) staining with histologic analysis in the largest reported cohort of adult subjects with KS.

DESIGN

A retrospective cohort study.

SETTING

Infertility Clinic and Institute for Regenerative Medicine.

PATIENT(S)

This study consisted of 79 adult subjects with KS and 12 adult control subjects.

INTERVENTION(S)

The subjects with KS (n = 79) underwent bilateral testicular biopsy in an initial effort to recover spermatozoa for in vitro fertilization and intracytoplasmic sperm injection. The institutional review board approved the use of a portion of the archived diagnostic pathology paraffin blocks for the study. The samples were superimposed onto microscopic slides and labeled with the PGP9.5 and MAGE-A4 antibodies. Subjects (n = 12) who had previously consented to be organ donors via the National Disease Research Interchange were selected as controls. Dedicated genitourinary pathologists examined the H & E-, PGP9.5-, and MAGE-A4-stained tissue for presence of undifferentiated spermatogonia and spermatozoa with the use of a virtual microscopy software.

MAIN OUTCOME MEASURE(S)

The primary outcome was the presence of MAGE-A4-positive or UCHL1-positive tubules that indicate undifferentiated spermatogonia. Supportive outcomes include assessing the biopsy specimen for the following: total surface area; total seminiferous tubule surface area; total interstitium surface area; the total number of seminiferous tubules; and MAGE-A4- negative or UCHL1-negative tubules. Additionally, clinical information, such as age, karyotype, height, weight, mean testicle size, and hormonal panel (luteinizing hormone, follicle-stimulating hormone, and testosterone), was obtained and used in a single and multivariable analysis with linear regression to determine predictive factors for the number of UCHL1-positive tubules.

RESULT(S)

The mean age of the subjects in the KS group was 32.9 ± 0.7 years (range, 16-48). UCHL1 (PGP9.5) and MAGE-A4 staining showed that 74.7% (n = 59) and 40.5% (n = 32) of the subjects with KS, respectively, were positive for undifferentiated spermatogonia compared with 100% (n = 12) of the control subjects who were positive for both the markers. Hematoxylin and eosin with microscopic analysis showed that only 10.1% (n = 8) of the subjects were positive for spermatogonia. The mean number of positive tubules per subject with KS was 11.8 ± 1.8 for UCHL1 and 3.7 ± 1.0 for MAGE-A4. Secondary analysis showed 7 (8.9%) adult subjects with KS as positive for spermatozoa on biopsy. The population having negative testicular sperm extraction results (n = 72) showed a spermatogonia-positive rate of 1.4%, (n = 1), 72.2% (n = 52), and 34.7% (n = 25) using H & E, UCHL1, and MAGE-A4, respectively. Further analysis showed that 54 (75.0%) subjects were either positive for UCHL1 or MAGE-A4. Twenty (27.8%) subjects were positive for both UCHL1 and MAGE-A4. Multivariate analysis with linear regression showed no significant correlation between clinical variables and the number of UCHL1-positive tubules found on biopsy specimens.

CONCLUSION(S)

We report a cohort of adult subjects with KS undergoing analysis for the presence of undifferentiated spermatogonia. UCHL1 and MAGE-A4 immunostaining appear to be an effective way of identifying undifferentiated spermatogonia in testicular biopsy specimens of subjects with KS. Despite observing deterioration in the testicular architecture, many patients remain positive for undifferentiated spermatogonia, which could be harvested and potentially used for infertility therapy in a patient with KS who is azoospermic and has negative testicular sperm extraction results.

A systemic review and meta-analysis exploring the predictors of sperm retrieval in patients with non-obstructive azoospermia and chromosomal abnormalities

To identify the most prevalent chromosomal abnormalities in patients with non-obstructive azoospermia (NOA), consolidate their surgical sperm retrieval (SSR) rates and determine the significant predictors of positive SSR in this patient population. A systematic review and meta-analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifty-three studies including 2965 patients were identified through searching the PubMed database. Klinefelter Syndrome (KS) was the most prevalent chromosomal abnormality reported in 2239 cases (75.5%). Azoospermia factor c (AZFc) microdeletions were the second most common (18.6%), but men with these deletions had higher SSR rates than patients with KS (41.95% with AZFc vs. 38.63% with KS). When examining predictors of SSR in KS patients, younger age was a significant predictor of positive SSR in patients undergoing microsurgical testicular sperm extraction (micro-TESE). Higher testosterone was a favourable predictor in those undergoing micro-TESE and conventional TESE. Lower luteinizing hormone (LH) and follicular stimulating hormone (FSH) values were significantly associated with positive SSR with testicular sperm aspiration (TESA). No parameter predicted SSR rates in patients with AZFc microdeletions. Overall, genetic abnormalities have significant implications on SSR success in patients with NOA.

At what age should we attempt to retrieve sperm from males with Klinefelter syndrome

Klinefelter syndrome (KS) is a common disorder and almost every clinician in almost every sub-specialty of medicine will knowingly or unwittingly treat boys or men with a 47,XXY chromosomal constitution. Although there are numerous aspects of KS worthy of discussion, this contribution will focus specifically on the controversial, and as yet unresolved, issue of whether it is advantageous to harvest testis tissue from peri-pubertal or adolescent boys with KS in a heroic effort to preserve that child’s chances of reproduction in his future adult life. What would be the rationale for that, how does the biology of spermatogenesis in the Klinefelter testis impact that decision, and what does the data show? The answer, assembled from a selection of seemingly disparate sources and directions, appears to be “No”. We do not have to advocate for an aggressive approach, we do not have to preemptively preserve future fertility. We can justifiably wait until adulthood with equivalent chances of success.

Female human primordial germ cells display X-chromosome dosage compensation despite the absence of X-inactivation

X-chromosome dosage compensation in female placental mammals is achieved by X-chromosome inactivation (XCI). An exception are human pre-implantation embryos, where dosage compensation occurs by X-chromosome dampening (XCD). Here, we examined whether XCD extends to human prenatal germ cells given their similarities with naïve pluripotent cells. We found that female human primordial germ cells (hPGCs) display reduced X-linked gene expression before entering meiosis. Moreover, in hPGCs, both X-chromosome are active and express the long non-coding RNAs XACT and XIST, the master regulator of XCI, which are silenced upon entry into meiosis. These findings uncover XACT as hPGC-marker, describe XCD associated with XIST-expression in hPGCs, and suggest that XCD evolved in humans to regulate X-linked genes in pre-implantation embryos and PGCs. Additionally, we found a unique X-chromosome regulation in human primordial oocytes. Therefore, future studies of human germline development must consider the sexually dimorphic X-chromosome dosage compensation mechanisms in the prenatal germline.

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.

Age-related presence of spermatogonia in patients with Klinefelter syndrome: a systematic review and meta-analysis

BACKGROUND

Klinefelter syndrome (KS) has been defined by sex chromosome aneuploidies (classically 47, XXY) in the male patient. The peripubertal timeframe in KS patients has been associated with the initiation of progressive testicular fibrosis, loss of spermatogonial stem cells (SSC), hypogonadism and impaired fertility. Less than half of KS patients are positive for spermatozoa in the ejaculate or testis via semen analysis or testicular sperm extraction, respectively. However, the chance of finding spermatogonia including a sub-population of SSCs in KS testes has not been well defined. Given the recent demonstration of successful cell culture for mouse and human SSCs, it could be feasible to isolate and propagate SSCs and transplant the cells back to the patient or to differentiate them in vitro to haploid cells.

OBJECTIVE AND RATIONALE

The main objective of this study was to meta-analyse the currently available data from KS patients to identify the prevalence of KS patients with spermatogonia on testicular biopsy across four age groups (year): fetal/infantile (age ≤ 1), prepubertal (age 1 ≤ x ≤ 10), peripubertal/adolescent (age 10 < x < 18) and adult (age ≥ 18) ages. Additionally, the association of endocrine parameters with presence or absence of spermatogonia was tested to obtain a more powered analysis of whether FSH, LH, testosterone and inhibin B can serve as predictive markers for successful spermatogonia retrieval.

SEARCH METHODS

A thorough Medline/PubMed search was conducted using the following search terms: 'Klinefelter, germ cells, spermatogenesis and spermatogonia', yielding results from 1 October 1965 to 3 February 2019. Relevant articles were added from the bibliographies of selected articles. Exclusion criteria included non-English language, abstracts only, non-human data and review papers.

OUTCOMES

A total of 751 papers were identified with independent review returning 36 papers with relevant information for meta-analysis on 386 patients. For the most part, articles were case reports, case-controlled series and cohort studies (level IV-VI evidence). Spermatogonial cells were present in all of the fetal/infantile and 83% of the prepubertal patients' testes, and in 42.7% and 48.5% of the peripubertal and adult groups, respectively were positive for spermatogonia. Additionally, 26 of the 56 (46.4%) peripubertal/adolescent and 37 of the 152 (24.3%) adult patients negative for spermatozoa were positive for spermatogonia (P < 0.05). In peripubertal/adolescent patients, the mean ± SEM level for FSH was 12.88 ± 3.13 IU/L for spermatogonia positive patients and 30.42 ± 4.05 IU/L for spermatogonia negative patients (P = 0.001); the mean ± SEM level LH levels were 4.36 ± 1.31 and 11.43 ± 1.68 IU/L for spermatogonia positive and negative, respectively (P < 0.01); the mean ± SEM level for testosterone levels were 5.04 ± 1.37 and 9.05 ± 0.94 nmol/L (equal to 145 ± 40 and 261 ± 27 and ng/dl) for the spermatogonia positive and negative groups, respectively (P < 0.05), while the difference in means for inhibin B was not statistically significant (P > 0.05). A similar analysis in the adult group showed the FSH levels in spermatogonia positive and negative patients to be 25.77 ± 2.78 and 36.12 ± 2.90 IU/L, respectively (mean ± SEM level, P < 0.05). All other hormone measurements were not statistically significantly different between groups.

WIDER IMPLICATIONS

While azoospermia is a common finding in the KS patient population, many patients are positive for spermatogonia. Recent advances in SSC in vitro propagation, transplantation and differentiation open new avenues for these patients for fertility preservation. This would offer a new subset of KS patients a chance of biological paternity. Data surrounding the hormonal profiles of KS patients and their relation to fertility should be interpreted with caution as a paucity of adequately powered data exists. Future work is needed to clarify the utility of FSH, LH, testosterone and inhibin B as biomarkers for successful retrieval of spermatogonia.

ART strategies in Klinefelter syndrome

PURPOSE

Patients with Klinefelter syndrome (KS) who receive assisted reproductive technology (ART) treatment often experience poor pregnancy rates due to decreased fertilization, cleavage, and implantation rates and even an increased miscarriage rate. Mounting evidence from recent studies has shown that various technological advances and approaches could facilitate the success of ART treatment for KS patients. In this review, we summarize the methods for guiding KS patients during ART and for developing optimal strategies for preserving fertility, improving pregnancy rate and live birth rate, and avoiding the birth of KS infants.

METHODS

We searched PubMed and Google Scholar publications related to KS patients on topics of controlled ovarian stimulation protocols, sperm extraction, fertility preservation, gamete artificial activation, round spermatid injection (ROSI), and non-invasive prenatal screening (PGD) methods.

RESULTS

This review outlines the different ovulation-inducing treatments for female partners according to the individual sperm status in the KS patient. We further summarize the methods of retrieving sperm, storing, and freezing rare sperm. We reviewed different methods of gamete artificial activation and discussed the feasibility of ROSI for sterile KS patients who absolutely lack sperm. The activation of eggs in the process of intracytoplasmic sperm injection and non-invasive PGD are urgently needed to prevent the birth of KS infants.

CONCLUSION

The integrated strategies will pave the way for the establishment of ART treatment approaches and improve the clinical outcome for KS patients.

Germ cell loss in Klinefelter syndrome: When and why?

Klinefelter syndrome (KS) is a quite common disorder with an incidence of 1-2 in 1,000 new-born males. Most patients are diagnosed in the light of a clinical checkup when consulting a fertility clinic with an unfulfilled child wish. Infertility in KS patients is caused by a massive germ cell loss, leading to azoospermia in more than 90% of the adult patients. Most seminiferous tubules in the adult KS testis are degenerated or hyalinized and testicular fibrosis can be observed, starting from puberty. However, focal spermatogenesis can be found in the testis of some patients. This offers the opportunity to extract spermatozoa from the testis by testicular sperm extraction (TESE). Nevertheless, TESE is only successful in about half of the KS adults seeking to father children. The reason for the germ cell loss remains unclear. To date, it is still debated whether the testicular tissue changes and the germ cell loss seen in KS is directly caused by an altered X-linked gene expression, the altered somatic environment, or a deficiency in the germ cells. In this review, we provide an overview of the current knowledge about the germ cell loss in KS patients.

Detection of low-grade mosaicism and its correlation with hormonal profile, testicular volume, and semen quality in a cohort of Egyptian Klinefelter and Klinefelter-like patients

Klinefelter syndrome (KS) is the most common chromosomal syndrome, causing infertility in men and leading to non-obstructive azoospermia. Previous studies on mosaicism have shown contradictory results on its correlation with both serum hormone levels and the presence of spermatozoa in the ejaculate of KS, KS-like, and non-KS-like infertile patients. So, the present study was designed to detect low-grade mosaicism in the peripheral blood lymphocytes and buccal mucosa cells of 14 KS and 8 KS-like patients by using fluorescence in situ hybridization (FISH) and to investigate its correlation with luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (T) levels, testicular volume, and semen analysis compared with 10 normal healthy fertile men. Our results indicated that mosaicism was only found in 42.9 % of the KS patients and completely absent in all KS-like patients. Moreover, mosaicism has led to complete azoospermia and non-significant differences in both hormone levels and testicular volume between mosaic and non-mosaic KS patients. All KS patients demonstrated significant differences in both hormone levels and testicular volume compared with normal men. Conversely, they revealed non-significant differences in hormone levels and significant differences in testicular volume compared with KS-like patients. Additionally, the KS-like patients exhibited non-significant variations in both LH and FSH levels and significant variations in T level and testicular volume compared with normal men. Moreover, all KS-like patients had azoospermia, except for one patient who showed oligozoospermia. Therefore, no correlations were found either between mosaicism and serum hormone levels or with testicular volume and semen analysis.