Spermatogenesis in Klinefelter's syndrome

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.

Novel insights on testicular volume and testosterone replacement therapy in Klinefelter patients undergoing testicular sperm extraction. A retrospective clinical study

STUDY QUESTION

To investigate whether sperm recovery is related to clinical features, hormone parameters and testosterone replacement therapy (TRT) in patients with Klinefelter syndrome (KS).

SUMMARY ANSWER

This study provides three interesting insights: (i) the probability to retrieve sperm is not related to testicular volume; (ii) TRT does not affect sperm retrieval rate (SRR); and (iii) reduced levels of LH and FSH represent a negative predictor of sperm retrieval in patients with TRT.

WHAT IS KNOWN ALREADY

Classical KS shows a karyotype with one extra X chromosome in all of somatic cells and clinical manifestations characterized by hypergonadotropic hypogonadism and infertility.

STUDY DESIGN, SIZE AND DURATION

We performed a retrospective cohort study. Data from 111 consecutive KS azoospermic patients undergoing testicular sperm extraction (TESE) were collected from 2005 to 2016.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

Data on anthropometric parameters, reproductive hormones and testicular volumes were collected. SRR was related to clinical characteristics and compared between TRT and untreated patients.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 38 patients (34.2%) had successful sperm recovery. The comparison of clinical characteristics did not differ between patients with and without sperm recovery. Sperm retrieval was successful also in subjects with smaller testes. The comparison of SRR in patients with or without TRT was not different (33.3% vs 34.6%). In TRT group, LH and FSH levels were significantly lower in subjects with no sperm retrieval (P values, respectively, <.05 and <.001).

LIMITATIONS AND REASONS FOR CAUTION

Well-designed controlled studies are necessary to confirm these data aimed to set the best therapeutic approach for fertility management in hypogonadal patients with nonmosaic KS.

WIDER IMPLICATIONS OF THE FINDINGS

Age at TESE, anthropometric measures, testis volume, sex hormones levels and semen parameters are not predictive parameters of SRR. Among TRT patients, reduced gonadotropin is related to failure in sperm retrieval.

Managing infertility in patients with Klinefelter syndrome

Klinefelter syndrome (KS) is the most frequent chromosomal abnormality with a prevalence of 150 per 100,000 males. It is now well known that the phenotype of Klinefelter adults varies from individual to individual and one registry study indicates that approximately 75% of KS subjects are not diagnosed probably because of very mild phenotypes. Due to seminiferous tubule fibrosis KS patients have small testes and are infertile because of azoospermia (>90%) or severe oligozoospermia (<10%). Adoption or heterologous insemination has been used in the past to achieve paternity. Currently it is well known that with TESE/micro-TESE (TESE = TEsticular Sperm Extraction) spermatozoa can be found in the testes of 28-67% of KS patients. Predictive factors of sperm retrieval success/failure, such as reproductive hormone plasma levels, testis volume and age, have been evaluated without any positive results. By combining TESE/micro-TESE with intracytoplasmic sperm injection an average of 50% of these patients have the possibility of fathering children and the birth of more than 150 children with normal karyotype has been reported in the last 20 years. However couples with a Klinefelter partner must be informed of the increased risk of autosomal/sex chromosomes aberrations in the sperm and embryos and of the possibility of preimplantation genetic diagnosis which is currently suggested by a minority of authors.

Should non-mosaic Klinefelter syndrome men be labelled as infertile in 2009?

BACKGROUND

Klinefelter syndrome is a common genetic condition. Affected non-mosaic men are azoospermic and have been labelled as infertile. Despite reports that these men can have children using assisted reproduction techniques, it is not common practice in the UK to offer sperm retrieval to these men.

METHODS

Medline and EMBASE (1980-2009) were searched independently by two authors and all studies involving surgical sperm retrieval in non-mosaic Klinefelter syndrome were included. The primary outcome was success of surgical sperm retrieval and the secondary outcome was live birth rate.

RESULTS

The overall success rate for sperm retrieval was 44%, with a higher rate of success using micro-dissection testicular sperm aspiration (micro-TESE) (55%). This, along with ICSI, has led to the birth of 101 children. However, there are no known predictors for successful sperm retrieval. Although there are concerns about genetic risk to the offspring of non-mosaic Klinefelter patients, this risk has not been found to be greater than that of patients with non-obstructive azoospermia with normal karyotype.

CONCLUSIONS

It is possible for a man with non-mosaic Klinefelter to father a child. However, before these techniques are offered, some ethical issues need to be explored.

Occupational hazards to male fecundity

Research methods and knowledge in the field of male reproductive toxicology have gradually improved since reports in the late 1970s on severe impairment of spermatogenesis in workers with occupational exposure to certain chlorinated hydrocarbon pesticides (the nematocide 1,2-dibromochloropropan and the insecticide and fungicide chlordecone, but still we have only vague answers to basic questions about the overall significance of the environmental and occupational impact of these compounds on male reproductive capability.

Low semen volume in 47 adolescents and adults with 47,XXY Klinefelter or 46,XX male syndrome

Klinefelter syndrome is characterized by progressive testicular failure causing androgen deficiency and azoospermia in most patients. The aim of this study was to evaluate semen quality in consecutive patients with an additional X chromosome as compared with healthy males. Forty-seven males with non-mosaic 47,XXY (n = 40) or SRY-positive 46,XX male (n = 7) karyotypes aged 26.1 (range: 15.0-51.7) years participated. Semen quality was compared with 2136 (control group I) men from the general population aged 18.9 (17.9-28.6) years and with 349 fertile men (control group II) aged 30.9 (22.0-43.8) years. Semen volume adjusted for duration of abstinence was significantly smaller in the patients [2.0 (0.2-5.7) mL] when compared with control group I [3.1 (0.3-12.5) mL, p < 0.0001] and group II [3.6 (0.6-12.5) mL, p < 0.0001]. There was no difference in semen volume between 47,XXY and 46,XX males. All patients had azoospermia except two 47,XXY males aged 29 years who had sperm concentrations of 0.5 and 1.6 million/mL, respectively. We found significantly smaller semen volume in the patients when compared with controls, and the presence of motile spermatozoa in two out of 47 patients. The small semen volume supports the notion of 47,XXY patients being androgen insufficient despite serum testosterone levels within the normal range.

Natural history of seminiferous tubule degeneration in Klinefelter syndrome

Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates dramatically at the time of puberty with complete hyalinization of the seminiferous tubules, although a few tubules with spermatogenesis may be present in adult life. Activation of the pituitary-gonadal axis at 3 months of age is seen in Klinefelter boys similar to healthy boys. However, the level of testosterone in Klinefelter boys is significantly lower than in controls. After this 'minipuberty', the hormone levels decline to normal prepubertal levels until puberty. In puberty, an initial rise in testosterone, inhibin B, LH and FSH occurs in Klinefelter boys. However, the rise in testosterone levels off and ends at a low-normal level in young adults. Likewise, serum concentration of inhibin B exhibits a dramatic decline to a low, often undetectable level, concomitantly with a rise in FSH, reflecting the degeneration of the seminiferous tubules. Many hypotheses about the underlying mechanism of the depletion of the germ cells in Klinefelter males have been reported and include insufficient supranumerary X-chromosome inactivation, Leydig cell insufficiency and disturbed regulation of apoptosis of Sertoli and Leydig cells. However, at present, the exact mechanism remains unclear. In this article, we summarize current knowledge on the development of the classical endocrinological and histological features of 47,XXY males from fetus to adulthood and review the literature concerning the degeneration of the seminiferous tubules in this syndrome.

Partners of men with Klinefelter syndrome can benefit from assisted reproductive technologies

OBJECTIVE

To report the birth of a healthy female infant from a father with nonmosaic Klinefelter syndrome (KS) and document the experience of men with KS undergoing assisted conception.

DESIGN

Retrospective.

SETTING

Private IVF center.

PATIENT(S)

Twelve couples with male factor infertility due to Klinefelter syndrome undergoing assisted reproduction treatment.

INTERVENTION(S)

Controlled ovarian hyperstimulation, testicular sperm extraction, intracytoplasmic sperm injection (ICSI), round spermatid injection (ROSI), and preimplantation genetic diagnosis.

MAIN OUTCOME MEASURE(S)

Testicular sperm retrieval rate, fertilization rate, and pregnancy outcome.

RESULT(S)

There was a sufficient amount of motile sperm for injection into mature oocytes in 6 of the 11 testicular biopsies (54.5%). Fertilization rates for ICSI and ROSI cases were 54.2% and 41.6%, respectively. The pregnancy rate per ET was 27.2%. None of the ROSI cases resulted in pregnancy. Two patients had spontaneous abortions at 8 and 18 weeks of gestation, respectively. Only one patient delivered a healthy female baby after 36 weeks of an uneventful pregnancy.

CONCLUSION(S)

Men with KS can benefit from assisted reproductive technologies, and the testicular sperm retrieval rate among them is promising. Although sex chromosome aberrations among the embryos from men with KS are not common, couples can be offered preimplantation genetic diagnosis before ET.

Outcome of ICSI using fresh and cryopreserved-thawed testicular spermatozoa in patients with non-mosaic Klinefelter's syndrome

BACKGROUND

Recently, intracytoplasmic sperm injection (ICSI) of testicular spermatozoa retrieved surgically from patients with non-mosaic Klinefelter's syndrome resulted in several deliveries. The aim of this study was to evaluate the outcome of ICSI using fresh and cryopreserved-thawed testicular spermatozoa in these patients.

METHODS AND RESULTS

Following informed consent regarding the genetic risks of their potential offspring, mature testicular spermatozoa were found in five out of 12 (42%) patients who underwent testicular sperm extraction, and ICSI was performed while excess tissue was cryopreserved. The mean age of the patients was 28.7 +/- 3.6 (range 23-36 years). Their baseline FSH was elevated (mean 38.3 +/- 11.4; range 22-58 mIU/ml). All patients had small testicles of 2-4 ml in volume. The outcome of ICSI using fresh or cryopreserved-thawed testicular spermatozoa during five cycles in each group, was compared. No statistical significant difference was found in the two pronuclear fertilization rate (66 versus 58%), embryo cleavage rate (98 versus 90%) and embryo implantation rate (33.3 versus 21.4%) for fresh or cryopreserved sperm accordingly. The clinical outcome after using fresh testicular sperm included two singleton pregnancies (one delivered and one ongoing) and a triplet pregnancy resulting in a twin delivery (after reduction of an 47,XXY embryo). After using cryopreserved-thawed testicular spermatozoa, two pregnancies were obtained resulting in one delivery of twins and one early spontaneous abortion.

CONCLUSIONS

Outcome of ICSI using cryopreserved-thawed testicular spermatozoa of patients with non-mosaic Klinefelter's syndrome is comparable with that following the use of fresh spermatozoa. The genetic implications for the future offspring should be explained to the patients.

Genetic risks of intracytoplasmic sperm injection in the treatment of male infertility: recommendations for genetic counseling and screening

OBJECTIVE

To review the most clinically significant genetic disorders associated with severe oligospermia and azoospermia in males, and to present recommendations for the genetic counseling and screening of infertile males and their partners before undertaking intracytoplasmic sperm injection (ICSI)-assisted reproduction.

DESIGN

The literature on genetic disorders associated with severe oligospermia and azoospermia was reviewed, and the most recent outcome data from surveys of ICSI-derived offspring are presented. Studies related to this topic were identified through MEDLINE.

RESULT(S)

Genetic disorders are not infrequent causes of severe oligospermia and azoospermia in males undergoing ICSI-assisted reproduction. The application of ICSI in the treatment of oligospermic or azoospermic males may result in the transmission or de novo introduction of genetic mutations or chromosomal abnormalities in their offspring. Genetic counseling and appropriate screening of couples with male infertility should be performed before their undertaking ICSI-assisted reproduction.

CONCLUSIONS

An understanding of the genetic risks and possible consequences that are inherent when ICSI is used to assist fertilization in couples with male infertility is necessary for clinicians and their patients.

Quantitative and ultrastructural study of Leydig cells in Klinefelter's syndrome

This ultrastructural and quantitative study of Leydig cells in Klinefelter's syndrome has been performed using the entire testes obtained from four autopsies plus testicular biopsies from 20 patients. The total Leydig cell volume per testis in Klinefelter's syndrome was similar to that of control testes. However, the total number of Leydig cells per testis was significantly lower in the patients with Klinefelter's syndrome than in the controls. This may be attributed to the Leydig cell hypertrophy that these patients underwent. In patients with Klinefelter's syndrome the average volume of each Leydig cell was significantly higher than that of the controls. Electron microscopic findings revealed that besides ultrastructurally normal Leydig cells there were three other morphologically abnormal Leydig cell types: abnormally differentiated cells; multivacuolated cells; and immature Leydig cells. The ultrastructurally normal Leydig cells were probably the cells principally responsible for testosterone biosynthesis in these patients, whereas the other Leydig cell types were probably barely or not at all functional. The hypertrophy showed by the ultrastructurally normal Leydig cells may be interpreted as an attempt to increase testosterone production.

Synaptonemal complex studies in a mosaic 46,XY/47,XXY male

We describe the results of synaptonemal complex (SCs) studies by light (LM) and electron microscopy (EM) in a sterile 46,XY/47,XXY male mosaic. Meiotic studies showed an arrest at the first spermatocyte level. Pachytene figures showed three types of cells: (1) cells with normal SCs, normal sex vesicle, and a 23,XY constitution; (2) cells with no sex vesicle, normal pairing of SCs, and a 24, (?) constitution; and (3) cells with a normal sex vesicle and fragmented SCs.

47,XXY Klinefelter's syndrome with low FSH and LH levels and absence of Leydig cells

Examination of testicular biopsy from a patient with 47,XXY Klinefelter's syndrome revealed a diffuse hyalinization of seminiferous tubules as well as absence of mature Leydig cells. Ultrastructural findings showed some immature Leydig cells in the testicular interstitium. Hormone assays revealed low serum FSH and LH levels. The association of both, hormone assays and testicular morphologic pattern, suggests the presence of a Klinefelter's syndrome with hypogonadotropic hypogonadism.