Seminal haploid cell detection by flow cytometry in non-obstructive azoospermia: a good predictive parameter for testicular sperm extraction

Differentiation between nonobstructive azoospermia and obstructive azoospermia: then and now

ABSTRACT

Male infertility has seen an increase in prevalence with cases of azoospermia estimated to affect 10%-15% of infertile men. Confirmation of azoospermia subsequently necessitates an early causal differentiation between obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). Although less common when compared to NOA, OA can represent upward 20%-40% of cases of azoospermia. While there are a multitude of etiologies responsible for causing NOA and OA, correctly distinguishing between the two types of azoospermia has profound implications in managing the infertile male. This review represents an amalgamation of the current guidelines and literature which will supply the reproductive physician with a diagnostic armamentarium to properly distinguish between NOA and OA, therefore providing the best possible care to the infertile couple.

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.

Sperm recovery and ICSI outcomes in men with non-obstructive azoospermia: a systematic review and meta-analysis

BACKGROUND

Factor affecting sperm retrieval rate (SRR) or pregnancy rates (PR) after testicular sperm extraction (TESE) in patients with non-obstructive azoospermia (NOA) have not been systematically evaluated. In addition, although micro-TESE (mTESE) has been advocated as the gold standard for sperm retrieval in men with NOA, its superiority over conventional TESE (cTESE) remains conflicting.

OBJECTIVE AND RATIONALE

The objective was to perform a meta-analysis of the currently available studies comparing the techniques of sperm retrieval and to identify clinical and biochemical factors predicting SRR in men with NOA. In addition, PRs and live birth rates (LBRs), as derived from subjects with NOA post-ICSI, were also analysed as secondary outcomes.

SEARCH METHODS

An extensive Medline, Embase and Cochrane search was performed. All trials reporting SRR derived from cTESE or mTESE in patients with NOA and their specific determinants were included. Data derived from genetic causes of NOA or testicular sperm aspiration were excluded.

OUTCOMES

Out of 1236 studies, 117 studies met the inclusion criteria for this study, enrolling 21 404 patients with a mean age (± SD) of 35.0 ± 2.7 years. cTESE and mTESE were used in 56 and 43 studies, respectively. In addition, 10 studies used a mixed approach and 8 studies compared cTESE with mTESE approach. Overall, a SRR per TESE procedure of 47[45;49]% (mean percentage [95% CI]) was found. No differences were observed when mTESE was compared to cTESE (46[43;49]% for cTESE versus 46[42;49]% for mTESE). Meta-regression analysis demonstrated that SRR per cycle was independent of age and hormonal parameters at enrolment. However, the SRR increased as a function of testis volume. In particular, by applying ROC curve analysis, a mean testis volume higher than 12.5 ml predicted SRR >60% with an accuracy of 86.2% ± 0.01. In addition, SRR decreased as a function of the number of Klinefelter's syndrome cases included (S = -0.02[-0.04;-0.01]; P < 0.01. I = 0.12[-0.05;0.29]; P = 0.16). Information on fertility outcomes after ICSI was available in 42 studies. Overall, a total of 1096 biochemical pregnancies were reported (cumulative PR = 29[25;32]% per ICSI cycle). A similar rate was observed when LBR was analysed (569 live births with a cumulative LBR = 24[20;28]% per ICSI cycle). No influence of male and female age, mean testis volume or hormonal parameters on both PR and LBR per ICSI cycle was observed. Finally, a higher PR per ICSI cycle was observed when the use of fresh sperm was compared to cryopreserved sperm (PR = 35[30;40]%, versus 20[13;29]% respectively): however, this result was not confirmed when cumulative LBR per ICSI cycle was analysed (LBR = 30[20;41]% for fresh versus 20[12;31]% for cryopreserved sperm).

WIDER IMPLICATIONS

This analysis shows that cTESE/mTESE in subjects with NOA results in SRRs of up to 50%, with no differences when cTESE was compared to mTESE. Retrieved sperms resulted in a LBR of up to 28% ICSI cycle. Although no difference between techniques was found, to conclusively clarify if one technique is superior to the other, there is a need for a sufficiently powered and well-designed randomized controlled trial to compare mTESE to cTESE in men with NOA.

Predictive factors of successful microdissection testicular sperm extraction

Azoospermia in men requires microsurgical reconstruction or a procedure for sperm retrieval with assisted reproduction to allow fertility. While the chance of successful retrieval of sperm in men with obstructive azoospermia approaches >90%, the chances of sperm retrieval in men with non-obstructive azoospermia (NOA) are not as high. Conventional procedures such as fine needle aspiration of the testis, testicular biopsy and testicular sperm extraction are successful in 20-45% of men with NOA. With microdissection testicular sperm extraction (micro-TESE), the chance of successful retrieval can be up to 60%. Despite this increased success, the ability to counsel patients preoperatively on their probability of successful sperm retrieval has remained challenging. A combination of variables such as age, serum FSH and inhibin B levels, testicular size, genetic analysis, history of Klinefelter syndrome, history of cryptorchidism or varicocele and histopathology on diagnostic biopsy have provided some insight into the chance of successful sperm retrieval in men with NOA. The goal of this review was to evaluate the preoperative factors that are currently available to predict the outcome for success with micro-TESE.

Significance of inhibin B and anti-Müllerian hormone in seminal plasma: a preliminary study

OBJECTIVE

To evaluate the predictive value of seminal inhibin B and anti-Müllerian hormone (AMH) on the outcome of testicular sperm extraction (TESE) in patients with nonobstructive azoospermia.

DESIGN

Prospective study.

SETTING

Reproductive biology department.

PATIENT(S)

Forty-seven normospermic, 28 oligozoospermic, and 68 azoospermic patients.

INTERVENTION(S)

Testicular sperm extraction.

MAIN OUTCOME MEASURE(S)

Seminal inhibin B and AMH measure.

RESULT(S)

The seminal values of inhibin B and AMH are widely dispersed. Both inhibin B and AMH seminal values are significantly different between the three groups. The average rates of seminal AMH (not inhibin B) differ significantly according to the etiology of the azoospermia. Both seminal markers are correlated. A significant positive correlation could be observed between the seminal inhibin B and the sperm count, but not for AMH. A significant correlation also exists between seminal and serum inhibin B. The predictive value for TESE outcome of each parameter is rather low. Conversely, a logistic regression combining serum FSH, seminal inhibin B, and AMH produced a satisfying area under the curve of 0.985.

CONCLUSION(S)

Seminal inhibin B and AMH values are proposed. Separately, seminal markers are poor predictors of TESE outcome. A logistic regression model led to a satisfying area under the curve of 0.985.

The presence of germ cells in the semen of azoospermic, cryptozoospermic and severe oligozoospermic patients: stringent flow cytometric analysis and correlations with hormonal status

OBJECTIVE

To understand the clinical significance of immature germ cells commonly found in ejaculates with low sperm counts by a novel and stringent flow cytometric quantitative method. PATIENTS/MEASUREMENTS: A total of 65 azoospermic, 38 cryptozoospermic and 42 severe oligozoospermic patients underwent routine hormone and semen analysis. Cells from each ejaculate were stained for DNA and mitochondria and analysed as spermatozoa (HC), round spermatids (1N), primary spermatocytes (4N) or diploid cells (2N).

RESULTS

About 90% of HC particles were eliminated as contaminants of the spermatozoa population by the analysis of their laser light scatter pattern and mitochondria staining intensity. Ploidy identification accuracy was improved by selection of singlets and elimination of cell aggregates for analysis. Distribution peaks for HC, 1N and 4N cells were displayed in 53%, 56% and 25% ejaculates, respectively, with prevalence in severe oligozoospermia > cryptozoospermia > azoospermia. 1N cell numbers were correlated with 4N and HC cells. For HC and 1N cells, the number/ejaculate and the incidence of distribution peaks were correlated with serum testosterone levels, and inversely with FSH for HC, 1N and 4N cells, suggesting that the abnormal shedding of 1N and 4N germ cells is the consequence rather than the cause of spermatogenic failure in these patients. Ploidy data bear no association with clinical diagnosis except for Klinefelter patients.

CONCLUSION

Whereas incidence of HC cells in azoospermic ejaculates may suggest minimal spermatogenic activity which evades detection by routine semen analysis, the presence of 1N and 4N cells in semen of patients provides noninvasive information about their spermatogenic status.