Potential of testicular sperm to support embryonic development to the blastocyst stage is comparable to that of ejaculated sperm

ICSI using testicular spermatozoa after failure of ICSI with ejaculated spermatozoa could be a good choice: A propensity score-matched cohort study

BACKGROUND

Ejaculated spermatozoa are considered to possess a higher fertilisation potential than testicular spermatozoa. In selected cases, the use of testicular spermatozoa from non-azoospermic infertile men resulted in a higher implantation and pregnancy rate than the use of ejaculated spermatozoa.

OBJECTIVE

The primary objective was to compare the live birth rate and cumulative live birth rate between couples with failed intracytoplasmic sperm injection procedure using ejaculated spermatozoa who subsequently had an intracytoplasmic sperm injection cycle with testicular spermatozoa and those who subsequently had an intracytoplasmic sperm injection cycle with ejaculated spermatozoa. The secondary objective was to determine the indications for the use of testicular spermatozoa after intracytoplasmic sperm injection failure with ejaculated spermatozoa.

MATERIALS AND METHODS

A retrospective study of matched couples using propensity score matching analysis was performed. After an intracytoplasmic sperm injection failure (cycle_1), intracytoplasmic sperm injection with either ejaculated spermatozoa (ejaculated sperm group), or testicular spermatozoa (testicular sperm group), was performed (cycle_2). The matching was on intracytoplasmic sperm injection performed in cycle_1 according to spermatozoa used (testicular or ejaculated) in cycle_2. Logistic regression was used to evaluate the influence of sperm origin on cumulative live birth rate. Univariate analysis on parameters of cycle_1 was used to identify the prognostic factors to propose an intracytoplasmic sperm injection with testicular spermatozoa in case of cycle_1 failure. The study outcomes were live birth rate and cumulative live birth rate.

RESULTS

Among the 6034 couples available, 63 were selected to constitute the testicular sperm group and 63 were selected by propensity score matching to constitute the ejaculated sperm group. After matching, the DNA fragmentation index was higher in the testicular sperm group (13.43% ± 9.65% vs. 8.93% ± 4.47%, p = 0.013); no significant difference was observed for the fertilisation rate, the number of obtained embryos, blastulation rate and frozen embryo rate. In cycle_2, the live birth rate was higher in the testicular group (22.2% vs. 0.0%, p < 0.001), as was the cumulative live birth rate (25.4% vs. 6.3%, p = 0.065). The prognostic factors identified for the proposal of intracytoplasmic sperm injection procedure with testicular spermatozoa after intracytoplasmic sperm injection failure with ejaculated spermatozoa were: teratozoospermia, cryptozoospermia and high DNA fragmentation index.

DISCUSSION

According to the present study and current knowledge, the use of testicular spermatozoa after failed intracytoplasmic sperm injection procedure in non-azoospermic men could be proposed instead of sperm donation in case of high sperm DNA fragmentation index, cryptozoospermia and teratozoospermia. A good oocyte response to ovarian stimulation during the previous assisted reproductive technology attempt will increase the chance of success. Although the main limitation of the current study is its retrospective nature, the use of the propensity score matching to perform causal inference study increases its reliability.

CONCLUSION

The present study supports that the use of testicular spermatozoa outside the classical indication of azoospermia is a good option when the indication is well established. However, before proposing a testicular biopsy, an improvement in sperm characteristics should be considered by treating the causes of sperm alteration.

Evaluation of PGK2 and ACR proteins in seminal plasma: suggestion of potential new biomarkers for prediction of sperm retrieval in non-obstructive azoospermia patients

This study aimed to assess the role of testis-specific proteins, PGK2 and ACR, in the prediction of sperm retrieval results by microdissection testicular sperm extraction (micro-TESE) in men with non-obstructive azoospermia (NOA). This was a case-control study including 48 semen samples of NOA patients undergoing the micro-TESE procedure, 15 semen samples from normozoospermic men as the positive control, and 12 semen samples from obstructive azoospermia/post-vasectomy (OA/PV) as negative controls. We investigated the levels of PGK2 and ACR proteins by ELISA tests in seminal plasma samples. The ELISA results revealed a significantly higher concentration of PGK2 and ACR in the NOA patients with successful sperm retrieval (NOA+) in comparison to NOA patients with failed sperm retrieval (NOA-) group (p = 0.0001 in both cases). For the first time, the data from this study suggests that a seminal PGK2 concentration of 136.3 pg/ml and ACR concentration of 21.75 mIU/ml can be used as cut-off values for the prediction of micro-TESE outcomes in NOA patients. These findings may be useful to avoid unnecessary micro-TESE operations. Overall, the seminal levels of the PGK2 and ACR proteins may be useful in predicting sperm retrieval success by micro-TESE in NOA patients.

Telomere Length in Human Spermatogenic Cells as a New Potential Predictor of Clinical Outcomes in ART Treatment with Intracytoplasmic Injection of Testicular Spermatozoa

Predicting the clinical outcomes of intracytoplasmic sperm injection (ICSI) cycles that use the testicular spermatozoa of azoospermic patients presents a challenge. Thus, the development of additional approaches to assessing the competence of a testicular-sperm-derived embryo without causing damage to gametes or the embryo is necessary. One of the key parameters in determining such developmental competence is telomere length (TL). We aimed to analyze TLs in spermatogenic cells from the testicular biopsy samples of azoospermic patients and determine how this parameter influences embryo competence for pre- and post-implantation development. Using Q-FISH, we studied the TL of the chromosomes in spermatogonia and spermatocytes I from the TESE biopsy samples of 30 azoospermic patients. An increase in TL was detected during the differentiation from spermatogonia to spermatocytes I. The patients' testicular spermatozoa were used in 37 ICSI cycles that resulted in 22 embryo transfers. Nine pregnancies resulted, of which, one was ectopic and eight ended in birth. The analysis of embryological outcomes revealed a dependence between embryo competence for development to the blastocyst stage and the TL in spermatogenic cells. The TLs in spermatogonia and spermatocytes I in the testicular biopsy samples were found to be higher in patients whose testicular sperm ICSI cycles resulted in a birth. Therefore, the length of telomeres in spermatogenic cells can be considered as a potential prognostic criterion in assessing the competence of testicular-sperm-derived embryos for pre- and post-implantation development. The results of this study provide the basis for the development of a laboratory test for the prediction of testicular sperm ICSI cycle outcomes.

Double strand DNA breaks in sperm: the bad guy in the crowd

PURPOSE

The main objective of this opinion paper was to bring to light and enhance our understanding of the amount of double-strand DNA breaks in sperm and whether there is a threshold of no return when considering repair by the oocyte/embryo.

METHODS

A brief review of literature related to the theories proposed for the appearance of double-strand breaks in human spermatozoa. Further commentary regarding their detection, how oocytes or embryos may deal with them, and what are the consequences if they are not repaired. Finally, a strategy for dealing with patients who have higher levels of double-strand DNA breaks in sperm is proposed by reviewing and presenting data using testicular extracted sperm.

RESULTS

We propose a theory that a threshold may exist in the oocyte that allows either complete or partial DNA repair of impaired sperm. The closer that an embryo is exposed to the threshold, the more the effect on the ensuing embryo will fail to reach various milestones, including blastocyst stage, implantation, pregnancy loss, an adverse delivery outcome, or offspring health. We also present a summary of the role that testicular sperm extraction may play in improving outcomes for couples in which the male has a high double-strand DNA break level in his sperm.

CONCLUSIONS

Double-strand DNA breaks in sperm provide a greater stress on repair mechanisms and challenge the threshold of repair in oocytes. It is therefore imperative that we improve our understanding and diagnostic ability of sperm DNA, and in particular, how double-strand DNA breaks originate and how an oocyte or embryo is able to deal with them.

Switching to testicular sperm after a previous ICSI failure with ejaculated sperm significantly improves blastocyst quality without increasing aneuploidy risk

PURPOSE

The use of testicular sperm is confined to patients with azoospermia, but there is evidence to support its use in males with poor semen parameters and/or previous intracytoplasmic sperm injection (ICSI) failures with ejaculated spermatozoa. We compared the aneuploidy rate and quality between embryos derived from ICSI cycles with ejaculated sperm (EJ-ICSI) and those from ICSI cycles using testicular spermatozoa (TT-ICSI) within the same couple.

METHODS

Retrospective study of 27 couples who first underwent an EJ-ICSI cycle that did not result in a livebirth and afterwards a TT-ICSI cycle. Only the two closer cycles of each couple were included. Preimplantation genetic test for aneuploidies (PGT-A) was performed in both ICSI cycles and classic parameters of embryo quality were assessed until blastocyst-stage.

RESULTS

A total of 375 embryos from 54 ICSI cycles were evaluated. Aneuploidy rate was measured by two different parameters. Patients undergoing TT-ICSI presented a similar aneuploidy rate as EJ-ICSI group: 30.7% (23.4-38.0) vs 26.8% (18.1-35.5) per inseminated oocytes (P>0.05), and 76.2% (66.2-86.2) vs 72.1% (59.1-85.2) per the total number of biopsied embryos (P>0.05), respectively. Further, the good-quality blastocyst rate per correctly fertilized oocyte was significantly higher in TT-ICSI group (33.6% (30.4-36.9)) than EJ-ICSI group (24.2% (20.3-28.0)) (P<0.001).

CONCLUSIONS

Switching to testicular sperm for ICSI yielded better-quality blastocysts without affecting the chromosomal load of the embryos in non-azoospermic couples with a previous unsuccessful ICSI using ejaculated sperm. This strategy is a good option for couples seeking a livebirth who do not want to use donor sperm.

Comparison of the Effects of Different Testicular Sperm Extraction Methods on the Embryonic Development of Azoospermic Men in Intracytoplasmic Sperm Injection (ICSI) Cycles: A Retrospective Cohort Study

Background

The effects of different testicular sperm extraction methods on the embryonic development and clinical outcome of azoospermic men in intracytoplasmic sperm injection (ICSI) cycles have not been researched. Our goal was to evaluate the effect of different sperm retrieval methods used for patients with OA or NOA on the embryonic development and clinical outcomes during the ICSI cycles.

Methods

This was a retrospective cohort study. A total of 530 azoospermic patients who underwent 570 ICSI cycles met the study criteria. ICSI was performed using testicular sperm by TESA in 282 cycles (TESA group); ICSI with testicular sperm by mTESE was performed due to NOA in 90 cycles (mTESE group); ICSI with testicular sperm by MESA was performed in 198 cycles (MESA group). The embryonic development and clinical outcomes of the three groups were counted.

Results

The general characteristics of the three groups were comparable. Our findings showed that the three groups were matched in terms of infertility durations and age. The mean age and the mean BMI of the female partners were similar in the three groups. Also, our findings showed there were no significant differences in the three groups regarding day 3 of the menstrual cycle FSH and days of stimulation. The research results showed that the total dose of FSH and E2 on the HCG administration day was also not statistically different in the three groups. The number of oocytes retrieved had no significant differences in the three groups. However, the number of 2PNs per cycle and the number of cleavages per cycle were higher in the MESA group than in the other two groups; the TESA group and mTESE group were similar. The number of good quality D3 embryos and the number of good quality D5 embryos were significantly decreased in the mTESE group as compared to the other two groups. Good quality D3 embryos and the rate of good quality D5 embryos in the mTESE group were lower than those in the other two groups. Moreover, the clinical pregnancy rates of the TESA group (50.71%) and the MESA group (51.52%) were similar, but both were much higher than that of the mTESE group (32.22%).

Conclusions

The mTESE provides a good clinical outcome for NOA patients with severe spermatogenic impairment, including the rate of good quality D3 embryos, the rate of good quality D5 embryos, and the clinical pregnancy rate. However, our data suggested that both the TESA and MESA groups had better embryonic development and clinical outcomes than the mTESE group.

The Germ Cell-Specific Markers ZPBP2 and PGK2 in Testicular Biopsies Can Predict the Presence as well as the Quality of Sperm in Non-obstructive Azoospermia Patients

To assess the role of three testis-specific genes including ZPBP2, PGK2, and ACRV1 in the prediction of sperm retrieval result and quality of retrieved sperm by microdissection testicular sperm extraction (micro-TESE) in non-obstructive azoospermia (NOA) patients. This was a case-control study including 57 testicular samples of NOA patients including 32 patients with successful sperm retrieval (NOA+) and 25 patients with failed sperm retrieval (NOA-), and 9 samples of men with normal spermatogenesis in the testes as the positive control (OA). We investigated the expression of candidate genes by RT-qPCR and germ cell population patterns by DNA flow cytometry in testicular biopsy samples. The association between PGK2 expressions with the quality of retrieved spermatozoa was also evaluated. The RT-qPCR data revealed a significantly higher expression of ZPBP2 and PGK2 in the NOA+ in comparison to NOA- group (P = 0.002, and P = 0.002, respectively). Flow cytometry results revealed that the haploid cell percentage was significantly higher in NOA+ vs. NOA- group (P = 0.0001). In samples with a higher percentage of haploid cells, expression levels of ZPBP2 and PGK2 were higher (P = 0.001). The PGK2 expression was significantly associated with retrieved sperm quality (P = 0.01). Our results contribute to the search for the biomarkers for predicting the presence of testicular sperm and would be useful to avoid unnecessary multiple micro-TESE. Overall, the expression pattern of the ZPBP2 and PGK2 may be useful in predicting sperm recovery success and quality of retrieved sperm in NOA patients.

Sperm source does not affect the ICSI outcome of patients with severely compromised spermatogenesis

Patients with spermatogenic dysfunction may display sperm parameters ranging from extremely severe oligozoospermia (sperm count lower than 2 million/ml) to azoospermia. It has been proposed that, since these patients may have increased sperm DNA damage that could affect their ICSI outcome, the use of surgically retrieved testicular spermatozoa should be preferred to improve their chance of fathering their biological offspring. However, studies in this field have yielded conflicting results. The present study provides an updated assessment of this subject by comparing the ICSI outcome of 762 patients with nonobstructive azoospermia and 419 with sperm count lower than 2 million/ml (median sperm count 300,000/ml). Both groups were homogeneous for the number of retrieved and injected MII oocytes. No difference was seen in terms of fertilisation, clinical pregnancy and cumulative live birth rates. Only the number of injected MII oocytes was found to independently predict the live birth rate, even when adjusted for the number of transferred embryos (OR 1.10 (1.0-1.2, p = 0.038)). The results of the present study stand against the use of testicular spermatozoa in patients with extremely severe spermatogenic dysfunction with available spermatozoa in their ejaculate.

Testicular spermatozoon is superior to ejaculated spermatozoon for intracytoplasmic sperm injection to achieve pregnancy in infertile males with high sperm DNA damage

The purpose of this study was to compare the clinical outcome of testicular spermatozoon versus ejaculated spermatozoon in the treatment of infertile males with high sperm DNA damage, referred as sperm DNA fragmentation index (DFI), that attending intracytoplasmic sperm injection (ICSI) programme in terms of clinical pregnancy, births delivered as the primary and pregnancy loss and embryo fertilisation as the secondary outcome. A total of 102 males fulfilling the inclusion criteria were enrolled in the present study. Of the 102 males, 61 infertile males underwent testicular spermatozoon combined with ICSI while the remaining 41 males applied ejaculated spermatozoa in their first ICSI cycles, and the data of them were collected and analysed. In a 18-month follow-up, testicular spermatozoon achieved higher pregnancy rate and deliver rate than those in ejaculated sperm group (pregnancy rate, 36% vs. 14.6%, p = 0.017; deliver rate, 38.5% vs. 9.8%, p = 0.001). Nevertheless, there were no significant differences in the number of oocytes aspirated and number of embryos transferred between the two groups. Additionally, the fertilisation rate in the testicular sperm study cohort (70.4%) was also similar to that in the ejaculated sperm group (75.0%). Based on the current data, we conclude that testicular spermatozoon is the prior option in the treatment of infertile males with high sperm DFI in ICSI programme. More high-quality studies with larger samples size are needed in the future due to the relative small size and the nonrandomized design of the present study.