Use of a highly sensitive quantitative telomerase assay in intracytoplasmic sperm injection programmes for the treatment of 47,XXY non-mosaic Klinefelter men

Predictors of Successful Testicular Sperm Extraction: A New Era for Men with Non-Obstructive Azoospermia

Background/Objectives: Non-obstructive azoospermia (NOA) is a severe form of male infertility characterized by the absence of sperm in the ejaculate due to impaired spermatogenesis. Testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection is the primary treatment, but success rates are unpredictable, causing significant emotional and financial burdens. Traditional clinical and hormonal predictors have shown inconsistent reliability. This review aims to evaluate current and emerging non-invasive preoperative predictors of successful sperm retrieval in men with NOA, highlighting promising biomarkers and their potential clinical applications. Methods: A comprehensive literature review was conducted, examining studies on clinical and hormonal factors, imaging techniques, molecular biology biomarkers, and genetic testing related to TESE outcomes in NOA patients. The potential role of artificial intelligence and machine learning in enhancing predictive models was also explored. Results: Traditional predictors such as patient age, body mass index, infertility duration, testicular volume, and serum hormone levels (follicle-stimulating hormone, luteinizing hormone, inhibin B) have limited predictive value for TESE success. Emerging non-invasive biomarkers-including anti-Müllerian hormone levels, inhibin B to anti-Müllerian hormone ratio, specific microRNAs, long non-coding RNAs, circular RNAs, and germ-cell-specific proteins like TEX101-show promise in predicting successful sperm retrieval. Advanced imaging techniques like high-frequency ultrasound and functional magnetic resonance imaging offer potential but require further validation. Integrating molecular biomarkers with artificial intelligence and machine learning algorithms may enhance predictive accuracy. Conclusions: Predicting TESE outcomes in men with NOA remains challenging using conventional clinical and hormonal parameters. Emerging non-invasive biomarkers offer significant potential to improve predictive models but require validation through large-scale studies. Incorporating artificial intelligence and machine learning could further refine predictive accuracy, aiding clinical decision-making and improving patient counseling and treatment strategies in NOA.

The Klinefelter Syndrome and Testicular Sperm Retrieval Outcomes

Klinefelter syndrome (KS), caused by the presence of an extra X chromosome, is the most prevalent chromosomal sexual anomaly, with an estimated incidence of 1:500/1000 per male live birth (karyotype 47,XXY). High stature, tiny testicles, small penis, gynecomastia, feminine body proportions and hair, visceral obesity, and testicular failure are all symptoms of KS. Endocrine (osteoporosis, obesity, diabetes), musculoskeletal, cardiovascular, autoimmune disorders, cancer, neurocognitive disabilities, and infertility are also outcomes of KS. Causal theories are discussed in addition to hormonal characteristics and testicular histology. The retrieval of spermatozoa from the testicles for subsequent use in assisted reproduction treatments is discussed in the final sections. Despite testicular atrophy, reproductive treatments allow excellent results, with rates of 40–60% of spermatozoa recovery, 60% of clinical pregnancy, and 50% of newborns. This is followed by a review on the predictive factors for successful sperm retrieval. The risks of passing on the genetic defect to children are also discussed. Although the risk is low (0.63%) when compared to the general population (0.5–1%), patients should be informed about embryo selection through pre-implantation genetic testing (avoids clinical termination of pregnancy). Finally, readers are directed to a number of reviews where they can enhance their understanding of comprehensive diagnosis, clinical care, and fertility preservation.

Sperm recovery and ICSI outcomes in Klinefelter syndrome: a systematic review and meta-analysis

BACKGROUND

Specific factors underlying successful surgical sperm retrieval rates (SRR) or pregnancy rates (PR) after testicular sperm extraction (TESE) in adult patients with Klinefelter syndrome (KS) have not been completely clarified.

OBJECTIVE AND RATIONALE

The aim of this review was to meta-analyse the currently available data from subjects with KS regarding SRRs as the primary outcome. In addition, when available, PRs and live birth rates (LBRs) after the ICSI technique were also investigated as secondary outcomes.

SEARCH METHODS

An extensive Medline, Embase and Cochrane search was performed. All trials reporting SRR for conventional-TESE (cTESE) or micro-TESE (mTESE) and its specific determinants without any arbitrary restriction were included.

OUTCOMES

Out of 139 studies, 37 trials were included in the study, enrolling a total of 1248 patients with a mean age of 30.9 ± 5.6 years. The majority of the studies (n = 18) applied mTESE, 13 applied cTESE and in one case testicular sperm aspiration (TESA) was used. Additionally, four studies used a mixed approach and in one study, the method applied for sperm retrieval was not specified. Overall, a SRR per TESE cycle of 44[39;48]% was detected. Similar results were observed when mTESE was compared to cTESE (SRR 43[35;50]% vs 45[38;52]% for cTESE vs micro-TESE, respectively; Q = 0.20, P = 0.65). Meta-regression analysis showed that none of the parameters tested, including age, testis volume and FSH, LH and testosterone (T) levels at enrollment, affected the final SRR. Similarly, no difference was observed when a bilateral procedure was compared to a unilateral approach. No sufficient data were available to evaluate the effect of previous T treatment on SRR. Information on fertility outcome after ICSI was available for 29 studies. Overall a total of 218 biochemical pregnancies after 410 ICSI cycles were observed (PR = 43[36;50]%). Similar results were observed when LBR was analyzed (LBR = 43[34;53]%). Similar to what was observed for SRR, no influence of KS age, mean testis volume, LH, FSH or total T levels on either PR and LBR was observed. No sufficient data were available to test the effect of the women's age or other female fertility problems on PR and LBR. Finally, no difference in PR or LBR was observed when the use of fresh sperm was compared to the utilization of cryopreserved sperm.

WIDER IMPLICATIONS

The present data suggest that performing TESE/micro-TESE in subjects with KS results in SRRs of close to 50%, and then PRs and LBRs of close to 50%, with the results being independent of any clinical or biochemical parameters tested.

Genetic and epigenetic risks of assisted reproduction

Assisted reproductive technology (ART) is used primarily for infertility treatments to achieve pregnancy and involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and cryopreservation. Moreover, preimplantation genetic diagnosis (PGD) of ART is used in couples for genetic reasons. In ART treatments, gametes and zygotes are exposed to a series of non-physiological processes and culture media. Although the majority of children born with this treatment are healthy, some concerns remain regarding the safety of this technology. Animal studies and follow-up studies of ART-borne children suggested that ART was associated with an increased incidence of genetic, physical, or developmental abnormalities, although there are also observations that contradict these findings. As IVF, ICSI, frozen-thawed embryo transfer, and PGD manipulate gametes and embryo at a time that is important for reprogramming, they may affect epigenetic stability, leading to gamete/embryo origins of adult diseases. In fact, ART offspring have been reported to have an increased risk of gamete/embryo origins of adult diseases, such as early-onset diabetes, cardiovascular disease, and so on. In this review, we will discuss evidence related to genetic, especially epigenetic, risks of assisted reproduction.

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.

Testicular function and fertility in men with Klinefelter syndrome: a review

Klinefelter syndrome, 47,XXY (KS), is the most frequent sex chromosome aberration in males, affecting 1 in 660 newborn boys. The syndrome is characterized by testicular destruction with extensive fibrosis and hyalinization of the seminiferous tubules resulting in small testes, hypergonadotropic hypogonadism, and azoospermia in the majority of cases. Until recently, infertility was considered an untreatable condition in KS. However, with the development of new advanced assisted reproductive techniques such as testicular sperm extraction (TESE) combined with ICSI it seems that KS patients should no longer be labelled as infertile. Especially, microdissection (micro)-TESE has proved to be an advantageous procedure for the identification of testicular spermatozoa in KS. The aim of this review was to describe current knowledge on the testicular changes occurring in KS, the associated changes in reproductive hormones and spermatogenesis, and the existing possibilities of biological fatherhood in 47,XXY patients.

The genetic causes of male factor infertility: a review

OBJECTIVE

To illustrate the necessity for an enhanced understanding of the genetic basis of male factor infertility, to present a comprehensive synopsis of these genetic elements, and to review techniques being utilized to produce new insights in fertility research.

BACKGROUND

Male factor infertility is a complex disorder that affects a large sector of the population; however, many of its etiologies are unknown. By elucidating the underlying genetic basis of infertile phenotypes, it may be possible to discover the causes of infertility and determine effective treatments for patients.

METHOD(S)

The PubMed database was consulted for the most relevant papers published in the last 3 years pertaining to male factor infertility using the keywords "genetics" and "male infertility."

RESULT(S)

Advances have been made in the characterization of the roles of specific genes, but further research is necessary before these results can be used as guidelines for diagnosing and treating male factor infertility. The accurate transmission of epigenetic information also has considerable influence on fertility in males and on the fertility of their offspring.

CONCLUSION(S)

Analysis of the genetic factors that impact male factor infertility will provide valuable insights into the creation of targeted treatments for patients and the determination of the causes of idiopathic infertility. Novel technologies that analyze the influence of genetics from a global perspective may lead to further developments in the understanding of the etiology of male factor infertility through the identification of specific infertile phenotype signatures.

Genetic and epigenetic risks of intracytoplasmic sperm injection method

Pregnancies achieved by assisted reproduction technologies, particularly by intracytoplasmic sperm injection (ICSI) procedures, are susceptible to genetic risks inherent to the male population treated with ICSI and additional risks inherent to this innovative procedure. The documented, as well as the theoretical, risks are discussed in the present review study. These risks mainly represent that consequences of the genetic abnormalities underlying male subfertility (or infertility) and might become stimulators for the development of novel approaches and applications in the treatment of infertility. In addition, risks with a polygenic background appearing at birth as congenital anomalies and other theoretical or stochastic risks are discussed. Recent data suggest that assisted reproductive technology might also affect epigenetic characteristics of the male gamete, the female gamete, or might have an impact on early embryogenesis. It might be also associated with an increased risk for genomic imprinting abnormalities.

Methylation status of the SNRPN and HUMARA genes in testicular biopsy samples

OBJECTIVE

To analyze the methylation status of two differentially inherited and methylated loci (the human androgen receptor [HUMARA] and the small nuclear ribonucleoprotein-associated polypeptide N [SNRPN] gene) in testicular biopsy samples, and to compare the results with microscopic evaluation.

DESIGN

Retrospective study.

SETTING

Infertility clinics and genetics laboratories.

PATIENT(S)

Twelve obstructive and 74 nonobstructive azoospermic men.

INTERVENTION(S)

Deoxyribonucleic acid samples from testicular biopsies and peripheral blood were modified with sodium bisulfite and amplified by methylation-specific polymerase chain reaction assay. Polymerase chain reaction primers specific for the methylated regions of the HUMARA locus and for the methylated and unmethylated CpG islands of the SNRPN gene were used.

MAIN OUTCOME MEASURE

Polymerase chain reaction product bands specific for methylated and unmethylated alleles.

RESULT(S)

Obstructive azoospermia patients were positive for spermatozoa and germ cells by all approaches (microscopic, HUMARA, and SNRPN analysis) with absolute consistency. In contrast, for the nonobstructive men, microscopy was consistent with SNRPN analysis as regards the presence of germ cells in 82% of the testicular tissues tested. Nonobstructive patients with maturation arrest were positive for the presence of germ cells only by HUMARA analysis, with 84% sensitivity.

CONCLUSION(S)

Methylation analysis of testicular tissue is consistent with microscopic analysis, in terms of the prevalence of germ cells and the stage of spermatogenic arrest in biopsy samples.

Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome

AIM

To study the occurrence of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome (KFS).

METHODS

Blood and semen samples were collected from azoospermic patients with KFS (n = 14) and a control group of men of proven fertility (n = 13). Semen analysis was done according to World Health Organization (WHO) guidelines. Blood samples were processed for karyotyping, fluorescent in situ hybridization (FISH) and measurement of plasma follicle stimulating hormone (FSH) by radioimmunoassay. To determine Y chromosome microdeletions, polymerase chain reaction (PCR) of 16 sequence tagged sites (STS) and three genes (DFFRY, XKRY and RBM1Y) was performed on isolated genomic DNA. Testicular fine needle aspiration cytology (FNAC) was done in selected cases.

RESULTS

Y chromosome microdeletions spanning the azoospermia factor (AZF)a and AZFb loci were found in four of the 14 azoospermic patients with KFS. Karyotype and FISH analysis revealed that, of the four cases showing Y chromosome microdeletion, three cases had a 47,XXY/46,XY chromosomal pattern and one case had a 46,XY/47,XXY/48,XXXY/48,XXYY chromosomal pattern. The testicular FNAC of one sample with Y chromosome microdeletion revealed Sertoli cell-only type of morphology. However, no Y chromosome microdeletions were observed in any of the 13 fertile men. All patients with KFS had elevated plasma FSH levels.

CONCLUSION

Patients with KFS may harbor Y chromosome microdeletions and screening for these should be a part of their diagnostic work-up, particularly in those considering assisted reproductive techniques.

Role of testicular tissue telomerase assay for the prediction of the presence of testicular spermatozoa in azoospermic men with varicoceles, pre- and post-varicocelectomy

We evaluated the reproductive potential of frozen/thawed testicular spermatozoa of azoospermic men with left varicocele. The role of testicular tissue telomerase assay (TTA) in the prediction of the presence of testicular spermatozoa pre- and post-varicocelectomy was investigated, as well. Therapeutic testicular biopsy and TTA were performed in 82 nonobstructed azoospermic (NOA) men with varicoceles. Testicular spermatozoa were found in 33 men and processed for cryopreservation. Oocytes were later recovered from the spouses of the latter azoospermic men with varicoceles and injected with frozen/thawed testicular spermatozoa. Among the 49 men who were negative for testicular spermatozoa, 22 men underwent subsequently subinguinal microsurgical varicocelectomy. A total of 198 mature oocytes were successfully injected and 101 were normally fertilized and subsequently cleaved. Transfer of these 101 embryos in 26 women resulted in nine full-term pregnancies. Thirteen healthy babies were delivered. A cut-off value of TTA of 39 TPG U microg(-1) protein had an overall diagnostic accuracy equal to 90.2% to predict the presence of testicular spermatozoa pre-varicocelectomy. Within the group of men who were negative for testicular spermatozoa a cut-off value of TTA equal to 28 TPG U microg(-1) protein (pre-varicocelectomy) had a 84.2 % diagnostic accuracy to recognize the men who would become positive for either ejaculated or testicular spermatozoa post-varicocelectomy. Testicular spermatozoa can be found in 40% of NOA men with left varicocele. Ooplasmic injections with frozen/thawed testicular spermatozoa have a role in the therapeutic management of non-obstructive azoospermia associated with varicocele. Pre-varicocelectomy, a TTA cut-off value equal to 39 TPG U microg(-1) protein has a 90.2% diagnostic accuracy to indicate the men positive/negative for testicular spermatozoa. In addition, pre-varicocelectomy, a cut-off value equal to 28 TPG U microg(-1) protein has a 84.2% diagnostic accuracy to identify those men with varicoceles without testicular spermatozoa, who will become positive/negative for spermatozoa (either ejaculated or testicular) post-varicocelectomy.

The role of ultrasonographically guided puncture of the human rete testis in the therapeutic management of nonobstructive azoospermia

We attempted to characterize the cells collected from the rete testis via ultrasonographically guided puncture. Unilateral puncture of the rete testis was performed in nine men with obstructive azoospermia and 51 men with nonobstructive azoospermia. All the aspirated samples from the rete testis were observed via confocal scanning laser microscope and some of them after fluorescent in situ hybridization techniques. Then therapeutic testicular biopsy was performed in the punctured testis of each man. Spermatozoa were found in all rete testis samples and all biopsy samples from obstructed men. Twenty-two nonobstructed men demonstrated absence of spermatozoa in biopsy samples. Twenty-nine nonobstructed men showed spermatozoa in biopsy material and 24 of these men (82%) had demonstrated spermatozoa in rete testis samples. There were no significant differences in fertilization and cleavage rate between intracytoplasmic sperm injection trials using biopsy spermatozoa and rete testis spermatozoa both in obstructed and nonobstructed men. Considering that puncture of the rete testis does not reduce the volume of testicular parenchyma, is less invasive and apparently causes less detrimental effect on testicular vasculature than biopsy, puncture of rete testis is recommended as first line approach for the treatment of azoospermic men. If puncture is negative for spermatozoa in nonobstructed men, biopsy is indicated.