Fourteen babies born after round spermatid injection into human oocytes

Use of assisted reproductive technologies (ARTs) to shorten the generational interval in ruminants: current status and perspectives

The challenges posed by climate change and increasing world population are stimulating renewed efforts for improving the sustainability of animal production. To meet such challenges, the contribution of genomic selection approaches, in combination with assisted reproductive technologies (ARTs), to spreading and preserving animal genetics is essential. The largest increase in genetic gain can be achieved by shortening the generation interval. This review provides an overview of the current status and progress of advanced ARTs that could be applied to reduce the generation time in both female and male of domestic ruminants. In females, the use of juvenile in vitro embryo transfer (JIVET) enables to generate offspring after the transfer of in vitro produced embryos derived from oocytes of prepubertal genetically superior donors reducing the generational interval and acceleration genetic gain. The current challenge is increasing in vitro embryo production (IVEP) from prepubertal derived oocytes which is still low and variable. The two main factors limiting IVEP success are the intrinsic quality of prepubertal oocytes and the culture systems for in vitro maturation (IVM). In males, advancements in ARTs are providing new strategies to in vitro propagate spermatogonia and differentiate them into mature sperm or even to recapitulate the whole process of spermatogenesis from embryonic stem cells. Moreover, the successful use of immature cells, such as round spermatids, for intracytoplasmic injection (ROSI) and IVEP could allow to complete the entire process in few months. However, these approaches have been successfully applied to human and mouse whereas only a few studies have been published in ruminants and results are still controversial. This is also dependent on the efficiency of ROSI that is limited by the current isolation and selection protocols of round spermatids. In conclusion, the current efforts for improving these reproductive methodologies could lead toward a significant reduction of the generational interval in livestock animals that could have a considerable impact on agriculture sustainability.

Aberrant histone methylation in mouse early preimplantation embryos derived from round spermatid injection

Round spermatid injection (ROSI) is the last resort and recourse for men with nonobstructive azoospermia to become biological fathers of their children. However, the ROSI-derived offspring rate is lower than intracytoplasmic sperm injection (ICSI) in mice (20% vs. 60%). This low success rate has hindered the spread of ROSI in ART (Assisted Reproductive Technology). However, the cause of the ROSI-zygote-derived low offspring rate is currently unknown. In the previous studies, we reported that H3K9me3 and H3K27me3 exhibited ectopic localizations in male pronuclei (mPN) of ROSI-zygotes, suggesting that the carried over histone to zygotes conveys epigenetic information. In this study, we analyzed other histone modifications to explore unknown abnormalities. H3K36me3 showed an increased methylation state compared to ICSI-derived embryos but not for H3K4me3. Abnormal H3K36me3 was corrected until 2-cell stage embryos, suggesting a long window of reprogramming ability in ROSI-embryos. Treatment with TSA of ROSI-zygotes, which was reported to be capable of correcting ectopic DNA methylation in ROSI-zygotes, caused abnormalities of H3K36me3 in male and female PN (fPN) of the zygotes. In contrast, round spermatid TSA treatment before ROSI, which was reported to improve the preimplantation development of ROSI-zygotes, showed beneficial effects without toxicity in fPN. Therefore, the results suggest that TSA has some negative effects, but overall, it is effective in the correction of epigenetic abnormalities in ROSI-zygotes. When attempting to correct epigenetic abnormalities, attention should be paid to epigenomes not only in male but also in female pronuclei.

The use of ICSI in ART: evidence for practice

This article reviews the evidence regarding the safety and efficacy of intra-cytoplasmic sperm injection (ICSI). It provides evidence-based clinical and laboratory guidelines and recommendations for use of ICSI within an assisted reproductive technology (ART) service. The guidelines address the evidence for the use of ICSI rather than conventional IVF (cIVF); the use of ART techniques supplementary to ICSI; and risks associated with ICSI. This article is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs and medical history of the patient, available resources, and institutional or clinical practice limitations.

Biallelic mutations in RNA-binding protein ADAD2 cause spermiogenic failure and non-obstructive azoospermia in humans

STUDY QUESTION

What are some pathogenic mutations for non-obstructive azoospermia (NOA) and their effects on spermatogenesis?

SUMMARY ANSWER

Biallelic missense and frameshift mutations in ADAD2 disrupt the differentiation of round spermatids to spermatozoa causing azoospermia in humans and mice.

WHAT IS KNOWN ALREADY

NOA is the most severe cause of male infertility characterized by an absence of sperm in the ejaculate due to impairment of spermatogenesis. In mice, the lack of the RNA-binding protein ADAD2 leads to a complete absence of sperm in epididymides due to failure of spemiogenesis, but the spermatogenic effects of ADAD2 mutations in human NOA-associated infertility require functional verification.

STUDY DESIGN SIZE DURATION

Six infertile male patients from three unrelated families were diagnosed with NOA at local hospitals in Pakistan based on infertility history, sex hormone levels, two semen analyses and scrotal ultrasound. Testicular biopsies were performed in two of the six patients. Adad2 mutant mice (Adad2^Mut/Mut) carrying mutations similar to those found in NOA patients were generated using the CRISPR/Cas9 genome editing tool. Reproductive phenotypes of Adad2^Mut/Mut mice were verified at 2 months of age. Round spermatids from the littermates of wild-type (WT) and Adad2^Mut/Mut mice were randomly selected and injected into stimulated WT oocytes. This round spermatid injection (ROSI) procedure was conducted with three biological replicates and >400 ROSI-derived zygotes were evaluated. The fertility of the ROSI-derived progeny was evaluated for three months in four Adad2^WT/Mut male mice and six Adad2^WT/Mut female mice. A total of 120 Adad2^Mut/Mut, Adad2^WT/Mut, and WT mice were used in this study. The entire study was conducted over 3 years.

PARTICIPANTS/MATERIALS SETTING METHODS

Whole-exome sequencing was performed to detect potentially pathogenic mutations in the six NOA-affected patients. The pathogenicity of the identified ADAD2 mutations was assessed and validated in human testicular tissues and in mouse models recapitulating the mutations in the NOA patients using quantitative PCR, western blotting, hematoxylin-eosin staining, Periodic acid-Schiff staining, and immunofluorescence. Round spermatids of WT and Adad2^Mut/Mut mice were collected by fluorescence-activated cell sorting and injected into stimulated WT oocytes. The development of ROSI-derived offspring was evaluated in the embryonic and postnatal stages.

MAIN RESULTS AND THE ROLE OF CHANCE

Three recessive mutations were identified in ADAD2 (MT1: c.G829T, p.G277C; MT2: c.G1192A, p.D398N; MT3: c.917_918del, p.Q306Rfs*43) in patients from three unrelated Pakistani families. MT1 and MT2 dramatically reduced the testicular expression of ADAD2, likely causing spermiogenesis failure in the NOA patients. Immunofluorescence analysis of the Adad2^Mut/Mut male mice with the corresponding MT3 mutation showed instability and premature degradation of the ADAD2 protein, resulting in the spermiogenesis deficiency phenotype. Through ROSI, the Adad2^Mut/Mut mice could produce pups with comparable embryonic development (46.7% in Adad2^Mut/Mut versus 50% in WT) and birth rates (21.45 ± 10.43% in Adad2^Mut/Mut versus 27.5 ± 3.536% in WT, P = 0.5044) to WT mice. The Adad2^WT/Mut progeny from ROSI (17 pups in total via three ROSI replicates) did not show overt developmental defects and had normal fertility.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

This is a preliminary report suggesting that ROSI can be an effective treatment for infertile Adad2^Mut/Mut mice. Further assisted reproductive attempts need to be carefully examined in humans during clinical trials.

WIDER IMPLICATIONS OF THE FINDINGS

Our work provides functional evidence that mutations in the ADAD2 gene are deleterious and cause consistent spermiogenic defects in both humans and mice. In addition, preliminary results show that ROSI can help Adad2^Mut/Mut to produce biological progeny. These findings provide valuable clues for genetic counselling on the ADAD2 mutants-associated infertility in human males.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the National Natural Science Foundation of China (32000587, U21A20204, and 32061143006), and the National Key Research and Developmental Program of China (2019YFA0802600 and 2021YFC2700202). This work was also supported by Institute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, China. The authors declare no competing interests.

Extending the culture of cleavage-stage embryos to the blastocyst stage after warming increases the chance of live birth: does it have a regenerative effect?

PURPOSE

We aimed to evaluate the effect of extending the culture of cleavage-stage embryos to the blastocyst stage in vitrified-warmed cycles on pregnancy outcomes.

METHODS

This is a retrospectively designed pilot study of a single center. All patients who applied for freeze-all cycle procedures during in vitro fertilization treatment were included in the study. Patients were classified into three subgroups. The embryos obtained were frozen at the cleavage or blastocyst stage. After a warming process, the cleavage-stage embryos were divided into two subgroups: the first group of embryos was transferred (vitrification day 3-embryo transfer (ET) day 3 (D3T3)) on the warming day; for the second group, the embryo culture was extended to the blastocyst stage (vitrification day 3-ET day 5 (after the extension of the embryo culture to the blastocyst stage), (D3T5)). Frozen blastocyst-stage embryos were transferred after warming (vitrification day 5-ET day 5 (D5T5)). Hormone replacement treatment was the only endometrial preparation regimen given during the embryo transfer cycle. The main outcome of the study was live birth rates. The clinical pregnancy rate and positive pregnancy test rate were determined as the secondary outcomes of the study.

RESULTS

The study included a total of 194 patients. The positive pregnancy test rates (PPR) and clinical pregnancy rates (CPR) of the D3T3, D3T5, and D5T5 groups were 14.0% and 59.2%; 43.8% and 9.3%; and 56.3% and 39.6%, respectively (p < 0.001 and p < 0.001). The live birth rates (LBR) of patients in the D3T3, D3T5, and D5T5 groups were 7.0%, 44.7%, and 27.1%, respectively (p < 0.001). In subgroup analysis of patients with a poor number of 2PN embryos (defined as having <  = 4 2PN embryos), the D3T5 group had significantly higher PPR (10.7%, 60.6%, 42.4%; p < 0.001), CPR (7.1%, 57.6%, 39.4%; p < 0.001), and LBR (3.6%, 39.4%, 21.2%; p: 0.001).

CONCLUSION

Extending the culture after warming to the blastocyst stage may be a better alternative than a cleavage-stage embryo transfer.

How to improve the clinical outcome of round spermatid injection (ROSI) into the oocyte: Correction of epigenetic abnormalities

Background

First successful human round spermatid injection (ROSI) was conducted by Tesarik et al. in 1996 for the sole treatment of nonobstructive azoospermic men whose most advanced spermatogenic cells were elongating round spermatids. Nine offsprings from ROSI were reported between 1996 and 2000. No successful deliveries were reported for 15 years after that. Tanaka et al. reported 90 babies born after ROSI and their follow-up studies in 2015 and 2018 showed no significant differences in comparison with those born after natural conception in terms of physical and cognitive abilities. However, clinical outcomes remain low.

Method

Clinical and laboratory data of successful cases in the precursor ROSI groups and those of Tanaka et al. were reviewed.

Results

Differences were found between the two groups in terms of identification of characteristics of round spermatid and oocyte activation. Additionally, epigenetic abnormalities were identified as underlying causes for poor ROSI results, besides correct identification of round spermatid and adequate oocyte activation. Correction of epigenetic errors could lead to optimal embryonic development.

Conclusion

Correction of epigenetic abnormalities has a probability to improve the clinical outcome of ROSI.

Co-Culture of Cryopreserved Healthy Sertoli Cells with Testicular Tissue of Non-Obstructive Azoospermia (NOA) Patients in Culture Media Containing Follicle-Stimulating Hormone (FSH)/Testosterone Has No Advantage in Germ Cell Maturation

Different cell culture conditions and techniques have been used to mature spermatogenic cells to increase the success of in vitro fertilization. Sertoli cells (SCs) are essential in maintaining spermatogenesis and FSH stimulation exerts its effect through direct or indirect actions on SCs. The effectiveness of FSH and testosterone added to the co-culture has been demonstrated in other studies to provide microenvironment conditions of the testicular niche and to contribute to the maturation and meiotic progression of spermatogonial stem cells (SSCs). In the present study, we investigated whether co-culture of healthy SCs with the patient's testicular tissue in the medium supplemented with FSH/testosterone provides an advantage in the differentiation and maturation of germ cells in NOA cases (N = 34). In men with obstructive azoospermia (N = 12), healthy SCs from testicular biopsies were identified and purified, then cryopreserved. The characterization of healthy SCs was done by flow cytometry (FC) and immunohistochemistry using antibodies specific for GATA4 and vimentin. FITC-conjugated annexin V/PI staining and the MTT assay were performed to compare the viability and proliferation of SCs before and after freezing. In annexin V staining, no difference was found in percentages of live and apoptotic SCs, and MTT showed that cryopreservation did not inhibit SC proliferation compared to the pre-freezing state. Then, tissue samples from NOA patients were processed in two separate environments containing FSH/testosterone and FSH/testosterone plus co-culture with thawed healthy SCs for 7 days. FC was used to measure 7th-day levels of specific markers expressed in spermatogonia (VASA), meiotic cells (CREM), and post-meiotic cells (protamine-2 and acrosin). VASA and acrosin basal levels were found to be lower in infertile patients compared to the OA group (8.2% vs. 30.6% and 12.8% vs. 30.5%, respectively; p < 0.05). Compared to pre-treatment measurements, on the 7th day in the FSH/testosterone environment, CREM levels increased by 58.8% and acrosin levels increased by 195.5% (p < 0.05). Similarly, in medium co-culture with healthy SCs, by day 7, CREM and acrosin levels increased to 92.2% and 204.8%, respectively (p < 0.05). Although VASA and protamine levels increased in both groups, they did not reach a significant level. No significant difference was found between the day 7 increase rates of CREM, VASA, acrosin and protamine-2 in either FSH/testosterone-containing medium or in medium additionally co-cultured with healthy SCs (58.8% vs. 92.2%, 120.6% vs. 79.4%, 195.5% vs. 204.8%, and 232.3% vs. 198.4%, respectively; p > 0.05). Our results suggest that the presence of the patient's own SCs for maturation of germ cells in the culture medium supplemented with FSH and testosterone is sufficient, and co-culture with healthy SCs does not have an additional advantage. In addition, the freezing-thawing process would not impair the viability and proliferation of SCs.

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.

Paternally inherited H3K27me3 affects chromatin accessibility in mouse embryos produced by round spermatid injection

Round spermatid injection (ROSI) results in a lower birth rate than intracytoplasmic sperm injection, which has hampered its clinical application. Inefficient development of ROSI embryos has been attributed to epigenetic abnormalities. However, the chromatin-based mechanism that underpins the low birth rate in ROSI remains to be determined. Here, we show that a repressive histone mark, H3K27me3, persists from mouse round spermatids into zygotes in ROSI and that round spermatid-derived H3K27me3 is associated with less accessible chromatin and impaired gene expression in ROSI embryos. These loci are initially marked by H3K27me3 but undergo histone modification remodelling in spermiogenesis, resulting in reduced H3K27me3 in normal spermatozoa. Therefore, the absence of epigenetic remodelling, presumably mediated by histone turnover during spermiogenesis, leads to dysregulation of chromatin accessibility and transcription in ROSI embryos. Thus, our results unveil a molecular logic, in which chromatin states in round spermatids impinge on chromatin accessibility and transcription in ROSI embryos, highlighting the importance of epigenetic remodelling during spermiogenesis in successful reproduction.

Single-cell multiomics sequencing reveals the reprogramming defects in embryos generated by round spermatid injection

Round spermatid injection (ROSI) technique holds great promise for clinical treatment of a proportion of infertile men. However, the compromised developmental potential of ROSI embryos largely limits the clinical application, and the mechanisms are not fully understood. Here, we describe the transcriptome, chromatin accessibility, and DNA methylation landscapes of mouse ROSI embryos derived from early-stage round spermatids using a single-cell multiomics sequencing approach. By interrogating these data, we identify the reprogramming defects in ROSI embryos at the pronuclear stages, which are mainly associated with the misexpression of a cohort of minor zygotic genome activation genes. We screen a small compound, A366, that can significantly increase the developmental potential of ROSI embryos, in which A366 can partially overcome the reprogramming defects by amending the epigenetic and transcriptomic states. Collectively, our study uncovers the reprogramming defects in ROSI embryos for understanding the mechanisms underlying compromised developmental potential and offers an avenue for ROSI technique optimization.

Spermatogonial Stem Cell-Based Therapies: Taking Preclinical Research to the Next Level

Fertility preservation via biobanking of testicular tissue retrieved from testicular biopsies is now generally recommended for boys who need to undergo gonadotoxic treatment prior to the onset of puberty, as a source of spermatogonial stem cells (SSCs). SSCs have the potential of forming spermatids and may be used for therapeutic fertility approaches later in life. Although in the past 30 years many milestones have been reached to work towards SSC-based fertility restoration therapies, including transplantation of SSCs, grafting of testicular tissue and various in vitro and ex vivo spermatogenesis approaches, unfortunately, all these fertility therapies are still in a preclinical phase and not yet available for patients who have become infertile because of their treatment during childhood. Therefore, it is now time to take the preclinical research towards SSC-based therapy to the next level to resolve major issues that impede clinical implementation. This review gives an outline of the state of the art of the effectiveness and safety of fertility preservation and SSC-based therapies and addresses the hurdles that need to be taken for optimal progression towards actual clinical implementation of safe and effective SSC-based fertility treatments in the near future.

Testis on a chip - a microfluidic 3-dimensional culture system for the development of spermatogenesisin-vitro

This research presents a novel Testis-on-a Chip- platform. Testicular cells are enzymatically isolated from the seminiferous tubules of sexually immature mice, seeded in a methylcellulose gel and cultured in a microfluidic chip. The unique design sandwiches the soft methylcellulose between stiffer agar support gels. The cells develop into organoids continuing to proliferate and differentiate. After seven weeks of culture the cells have over 95% viability. Confocal microscopy of the developed organoids reveals a structure containing the various stages of spermatogenesis up to and including meiosis II: premeiotic, meiotic and post-meiotic germ cells. The organoid structure also contains the supporting Sertoli and peritubular cells. The responsiveness of the system to the addition of testosterone and retinoic acid to the culture medium during the experiment are also investigated. As a benchmark, the Testis-on-a-Chip is compared to a conventional three-dimensional methylcellulose cell culture in a well plate. Analysis via FACS (Fluorescence-activated cell sorting) shows more haploid cells in the chip as compared to the plates. Immunofluorescence staining after seven weeks of culture shows more differentiated cells in the chip as compared to the well plate. This demonstrates the feasibility of our platform as well as its advantages. This research opens new horizons for the study and realization of spermatogenesis in-vitro. It can also enable the implementation of microfluidic technologies in future therapeutic strategies for pre pubertal male fertility preservation and adults with maturation arrest. Lastly, it can serve as a platform for drug and toxin testing.

Mysteries and unsolved problems of mammalian fertilization and related topics

Mammalian fertilization is a fascinating process that leads to the formation of a new individual. Eggs and sperm are complex cells that must meet at the appropriate time and position within the female reproductive tract for successful fertilization. I have been studying various aspects of mammalian fertilization over 60 years. In this review, I discuss many different aspects of mammalian fertilization, some of my laboratory's contribution to the field, and discuss enigmas and mysteries that remain to be solved.

Using publicly available transcriptomic data to identify mechanistic and diagnostic biomarkers in azoospermia and overall male infertility

Azoospermia, which is the absence of spermatozoa in an ejaculate occurring due to defects in sperm production, or the obstruction of the reproductive tract, affects about 1% of all men and is prevalent in up to 10–15% of infertile males. Conventional semen analysis remains the gold standard for diagnosing and treating male infertility; however, advances in molecular biology and bioinformatics now highlight the insufficiency thereof. Hence, the need to widen the scope of investigating the aetiology of male infertility stands pertinent. The current study aimed to identify common differentially expressed genes (DEGs) that might serve as potential biomarkers for non-obstructive azoospermia (NOA) and overall male infertility. DEGs across different datasets of transcriptomic profiling of testis from human patients with different causes of infertility/ impaired spermatogenesis and/or azoospermia were explored using the gene expression omnibus (GEO) database. Following the search using the GEOquery, 30 datasets were available, with 5 meeting the inclusion criteria. The DEGs for datasets were identified using limma R packages through the GEO2R tool. The annotated genes of the probes in each dataset were intersected with DEGs from all other datasets. Enriched Ontology Clustering for the identified genes was performed using Metascape to explore the possible connection or interaction between the genes. Twenty-five DEGs were shared between most of the datasets, which might indicate their role in the pathogenesis of male infertility. Of the 25 DEGs, eight genes (THEG, SPATA20, ROPN1L, GSTF1, TSSK1B, CABS1, ADAD1, RIMBP3) are either involved in the overall spermatogenic processes or at specific phases of spermatogenesis. We hypothesize that alteration in the expression of these genes leads to impaired spermatogenesis and, ultimately, male infertility. Thus, these genes can be used as potential biomarkers for the early detection of NOA.

Fertility preservation in boys facing gonadotoxic cancer therapy

Patient survival following childhood cancer has increased with contemporary radiation and chemotherapy techniques. However, gonadotoxicity associated with treatments means that infertility is a common consequence in survivors. Novel fertility preservation options are emerging, but knowledge about these options amongst urologists and other medical professionals is lacking. Pre-pubertal boys generally do not produce haploid germ cells. Thus, strategies for fertility preservation require cryopreservation of tissue containing spermatogonial stem cells (SSCs). Few centres worldwide routinely offer this option and fertility restoration (including testicular tissue engraftment, autotransplantation of SSCs and in vitro maturation of SSCs to spermatozoa) post-thaw is experimental. In pubertal boys, the main option for fertility preservation is masturbation and cryopreservation of the ejaculate. Assisted ejaculation using penile vibratory stimulation or electroejaculation and surgical sperm retrieval can be used in a sequential manner after failed masturbation. Physicians should inform boys and parents about the gonadotoxic effects of cancer treatment and offer fertility preservation. Preclinical experience has identified challenges in pre-pubertal fertility preservation, but available options are expected to be successful when today's pre-pubertal boys with cancer become adults. By contrast, fertility preservation in pubertal boys is clinically proven and should be offered to all patients undergoing cancer treatment.

Effect of testicular morphology on embryo development to the blastocyst stage after round spermatid injection

If spermatozoa cannot be found after testiculer sperm extraction (TESE) in patients followed up due to nonobstructive azospermia (NOA) and the patients do not want donor spermatozoa, performance of round spermatid injection (ROSI) with the current technology seems to be the last resort. This retrospective study was conducted to evaluate the effect of testicular morphology on the development of embryos to the blastocyst stage obtained from ROSI. Between September 2019 and March 2020, after TESE and biopsy 29 patients who had only spermatid were taken to study. Tubular appearance, basal membrane appearance, Johnson score, peritubular fibrosis, interstitial fibrosis, and Leydig cell proliferation were pathologically examined. Following egg collection, ROSI was applied to the oocytes using the piezoelectric method. The embryos were monitored until the blastocyst stage. The mean age of the 29 patients was 36.3±5.01 years. Also, 7 patients had not previously undergone TESE, 20 had previously undergone once, and 2 had previously undergone twice. It was observed that having a history of TESE and a high Johnson score increased the likelihood of the embryo remaining in the blastocyst stage (P=0.021 and 0.014, respectively). However, other parameters do not affect the likelihood of blastocyst formation (P>0.05). Low TESE history and high Johnson score were associated with embryo development to the blastocyst stage. If spermatozoa are not found in patients with nonobstructive azoospermia, ROSI performed during initial TESE increases the likelihood of blastocyst formation.

Tricostatin A-treated round spermatid enhances preimplantation embryo developmental competency following round spermatid injection in mice

It has been documented that the inefficacy of round spermatid injection (ROSI) might be caused by abnormal epigenetic modifications. Therefore, this study aimed to evaluate the effect of trichostatin A (TSA) as an epigenetic modifier of preimplantation embryo development in activated ROSI oocytes. Matured oocytes were collected from superovulated female mice. Testes were placed in human tubal fluid medium and masses were then cut into small pieces to disperse spermatogenic cells. Round spermatids were treated with TSA and subsequently injected into oocytes. The expression level of the development-related genes including Oct4, Sox2, Nanog, Dnmt and Hdac transcripts were evaluated using qRT-PCR. Immunohistochemistry was performed to confirm the presence of Oct-4 protein at the blastocyst stage. There was no statistically significant difference in fertilization rate following ROSI/+TSA compared with the non-treated ROSI and intracytoplasmic sperm injection (ICSI) groups. Importantly, TSA treatment increased blastocyst formation from 38% in non-treated ROSI to 68%. The relative expression level of developmentally related genes increased and Dnmt transcripts decreased in ROSI/+TSA-derived embryos, similar to the expression levels observed in the ICSI-derived embryos. In conclusion, our results indicate that spermatid treatment with TSA prior to ROSI would increase the success rate of development to the blastocyst stage and proportion of pluripotent cells.

Solid surface vitrification of goat testicular cell suspension enriched for spermatogonial stem cells

This study reports solid surface vitrification (SSV) of goat testicular cell suspensions (TCS) enriched for spermatogonial stem cells (SSCs). The TCS was isolated from pre-pubertal goat testis by enzymatic digestion, enriched for SSCs by filtration and differential plating, and were vitrified-warmed by SSV. The study showed that SSV could successfully vitrify goat TCS although the percentage of live cells in the vitrified-warmed group was lower (74.8 ± 4.1%) than in non-vitrified control (80.6 ± 6.27%). The vitrified-warmed TCS formed putative SSC colonies upon their in vitro culture, but the colony size of vitrified-warmed cells (24.3 ± 1.8 μm) was smaller than those of non-vitrified warmed cells (58.4 ± 2.5 μm). Mitochondrial activity (0.40 vs. 0.38 A U.), population doubling time (33.45 ± 1.25 h vs. 31.86 ± 1.90 h), and the cell proliferation rate (0.72 ± 0.10 vs. 0.75 ± 0.11 per day) of total cells (including putative SSCs and other somatic cells) did not differ (p > 0.05) between control and SSV vitrified-warmed groups. However, during in vitro culture for 96 h, vitrified-warmed cells showed significantly lower (0.75 vs. 1.33 A U.; p < 0.05) mitochondrial activity than non-vitrified controls. The DCFDA assay showed that ROS activity was significantly (p < 0.05) higher in vitrified-warmed cells (52.8 ± 4.1 A U) than non-vitrified control cells (32.8 ± 2.1 AU). In conclusion, our results suggest that SSC-enriched goat TCS could be successfully cryopreserved by SSV. However, ROS-induced damages to cell cytoplasmic components reduce their cellular proliferation and require further improvement in the protocol. To the best of our knowledge, this study is the first report on the SSV of SSC-enriched goat TCS.

Blastocyst development after fertilization with in vitro spermatids derived from nonhuman primate embryonic stem cells

OBJECTIVE

To demonstrate that functional spermatids can be derived in vitro from nonhuman primate pluripotent stem cells.

DESIGN

Green fluorescent protein-labeled, rhesus macaque nonhuman primate embryonic stem cells (nhpESCs) were differentiated into advanced male germ cell lineages using a modified serum-free spermatogonial stem cell culture medium. In vitro-derived round spermatid-like cells (rSLCs) from differentiated nhpESCs were assessed for their ability to fertilize rhesus oocytes by intracytoplasmic sperm(atid) injection.

SETTING

Multiple academic laboratory settings.

PATIENTS

Not applicable.

INTERVENTIONS

Intracytoplasmic sperm(atid) injection of in vitro-derived spermatids from nhpESCs into rhesus macaque oocytes.

MAIN OUTCOME MEASURES

Differentiation into spermatogenic cell lineages was measured through multiple assessments including ribonucleic acid sequencing and immunocytochemistry for various spermatogenic markers. In vitro spermatids were assessed for their ability to fertilize oocytes by intracytoplasmic sperm(atid) injection by assessing early fertilization events such as spermatid deoxyribonucleic acid decondensation and pronucleus formation/apposition. Preimplantation embryo development from the one-cell zygote stage to the blastocyst stage was also assessed.

RESULTS

Nonhuman primate embryonic stem cells can be differentiated into advanced germ cell lineages, including haploid rSLCs. These rSLCs undergo deoxyribonucleic acid decondensation and pronucleus formation/apposition when microinjected into rhesus macaque mature oocytes, which, after artificial activation and coinjection of ten-eleven translocation 3 protein, undergo embryonic divisions with approximately 12% developing successfully into expanded blastocysts.

CONCLUSIONS

This work demonstrates that rSLCs, generated in vitro from primate pluripotent stem cells, mimic many of the capabilities of in vivo round spermatids and perform events essential for preimplantation development. To our knowledge, this work represents, for the first time, that functional spermatid-like cells can be derived in vitro from primate pluripotent stem cells.

Infertility cell therapy and epigenetic insights

Recent advances in assisted reproductive technology (ART) have allowed couples with severe infertility to conceive, but the methods are not effective for all cases. Stem cells as undifferentiated cells which are found in different stages of embryonic, fetal and adult life are known to be capable of forming different cell types, tissues, and organs. Due to their unlimited resources and the incredible power of differentiation are considered as potential new therapeutic biological tools for treatment of infertility. For reproductive medicine, stem cells are stimulated in vitro to develop various specialized functional cells including male and female gametes. The epigenetic patterns can be modified in the genome under certain drugs exposure or lifestyle alterations. Therefore, epigenetics-related disorders may be treated if the nature of the modifications is completely admissible. It is proved that our understanding of epigenetic processes and its association with infertility would help us not only to understand the etiological factors but also to treat some type of male infertilities. Exploration of both genetic and epigenetic variations in the disease development could help in the identification of the interaction patterns between these two phenomena and possible improvement of therapeutic methods.

Clinical values and advances in round spermatid injection (ROSI)

Azoospermia is defined as the complete absence of sperm cells in the ejaculate. Approximately 10-15 % of infertile men display azoospermia. Azoospermia can be subdivided into two types, obstructive azoospermia (OA) and non-obstructive azoospermia (NOA). NOA azoospermia might be the result due to primary testicular damage, secondary testicular damage, or incomplete testicular development. NOA azoospermia accounts for a considerable proportion of male infertility. A significant percentage of men with NOA azoospermia have foci of active spermatogenesis up to the stage of round spermatid. Round spermatid injection (ROSI) is a technique of assisted in-vitro fertilization (IVF) in assisted reproductive technology (ART). ROSI technique involves the injection of haploid germ cells derived from testicular biopsies into the recipient oocytes. The present study demonstrates that more participants and long-term follow-up studies are required to assess the reliability of the ROSI technique. In order to increase the success rate of the ROSI technique, round spermatids should be correctly evaluated and selected. Our study refers to the clinical values, challenges, and innovations in round spermatid injection (ROSI).

Sperm Selection Procedures for Optimizing the Outcome of ICSI in Patients with NOA

Retrieving spermatozoa from the testicles has been a great hope for patients with non-obstructive azoospermia (NOA), but relevant methods have not yet been developed to the level necessary to provide resolutions for all cases of NOA. Although performing testicular sperm extraction under microscopic magnification has increased sperm retrieval rates, in vitro selection and processing of quality sperm plays an essential role in the success of in vitro fertilization. Moreover, sperm cryopreservation is widely used in assisted reproductive technologies, whether for therapeutic purposes or for future fertility preservation. In recent years, there have been new developments using advanced technologies to freeze and preserve even very small numbers of sperm for which conventional techniques are inadequate. The present review provides an up-to-date summary of current strategies for maximizing sperm recovery from surgically obtained testicular samples and, as an extension, optimization of in vitro sperm processing techniques in the management of NOA.

Questioning the utility of round spermatid injections in men with non-obstructive azoospermia

BACKGROUND

Data on who among the infertile male population may benefit from round spermatid injections (ROSI) are lacking.

OBJECTIVE

To determine the probability of finding round spermatids suitable for ROSI in men with non-obstructive azoospermia (NOA) in whom no spermatozoa were retrieved at testicular sperm extraction.

MATERIALS AND METHODS

Four-hundred fifty-seven consecutive men with azoospermia underwent testicular sperm extraction. Clinical examination included age, secondary sexual characteristics, testicular size, reproductive hormone estimation, karyotyping, and Y chromosome microdeletion analyses. Histologic examination was performed, and histologic classification was determined by the most advanced spermatogenetic cell identified in the combined histologic and cytologic examination.

RESULTS

Of the 457 azoospermic men, 342 were diagnosed with NOA, and 148 (148/342, 43%) had mixed atrophy on histopathology and retrievable spermatozoa. No spermatozoa were found in 194/342 men with NOA (57%). Histopathology diagnosed 145/194 (75%) of them with Sertoli cell only, 45/194 (23%) with spermatocyte maturation arrest, and 4/194 (2%) with spermatid maturation arrest.

CONCLUSIONS

Histopathologically identified round spermatids without spermatozoa were rare in men with NOA. Only very few of them are likely to reap the benefits of ROSI, thus presenting the need to reconsider its actual clinical value.

Transfer- or 'transmission'-RNA fragments? The roles of tsRNAs in the reproductive system

Transfer-RNAs (tRNAs) help ribosomes decode mRNAs and synthesize proteins; however, tRNA fragments produced under certain conditions, known as tRNA-derived small RNAs (tsRNAs), have been found to play important roles in pathophysiological processes. In the reproductive system, tsRNAs are abundant in gametes and embryos and at the maternal-fetal interface, as well as in microvesicles like epididymosomes, seminal plasma exosomes, and syncytiotrophoblast-derived extracellular vesicles. tsRNAs can affect gamete cell maturation, zygote activation, and early embryonic development. tsRNAs can transmit epigenetic information to later generations. In particular, exposure to environmental factors such as nutrition, isoproterenol, and poly(I:C) may allow tsRNAs to transfer information to the gametes or placenta to alter offspring phenotype. The underlying mechanisms of tsRNAs action include transposon silencing, translation regulation, and target mRNA degradation. Herein, we review the currently reported tsRNAs in the reproductive system, their validated functions, and potential roles. A better understanding of this field may help to provide useful recommendations or develop strategies to increase fertility and conception of healthy babies.

Strategies for cryopreservation of testicular cells and tissues in cancer and genetic diseases

Cryopreservation of testicular cells and tissues is useful for the preservation and restoration of fertility in pre-pubertal males expecting gonadotoxic treatment for cancer and genetic diseases causing impaired spermatogenesis. A number of freezing and vitrification protocols have thus been tried and variable results have been reported in terms of cell viability spermatogenesis progression and the production of fertile spermatozoa. A few studies have also reported the production of live offspring from cryopreserved testicular stem cells and tissues in rodents but their replication in large animals and human have been lacking. Advancement in in vitro spermatogenesis system has improved the possibility of producing fertile spermatozoa from the cryopreserved testis and has reduced the dependency on transplantation. This review provides an update on various cryopreservation strategies for fertility preservation in males expecting gonadotoxic treatment. It also discusses various methods of assessing and ameliorating cryoinjuries. Newer developments on in vitro spermatogenesis and testicular tissue engineering for in vitro sperm production from cryopreserved SSCs and testicular tissue are also discussed.

Transcriptome and DNA Methylation Profiles of Mouse Fetus and Placenta Generated by Round Spermatid Injection

Low birth efficiency and developmental abnormalities in embryos derived using round spermatid injection (ROSI) limit the clinical application of this method. Further, the underlying molecular mechanisms remain elusive and warrant further in-depth study. In this study, the embryonic day (E) 11.5 mouse fetuses and corresponding placentas derived upon using ROSI, intracytoplasmic sperm injection (ICSI), and natural in vivo fertilized (control) embryos were collected. Transcriptome and DNA methylation profiles were analyzed and compared using RNA-sequencing (RNA-seq) and whole-genome bisulfite sequencing, respectively. RNA-seq results revealed similar gene expression profiles in the ROSI, ICSI, and control fetuses and placentas. Compared with the other two groups, seven differentially expressed genes (DEGs) were identified in ROSI fetuses, and ten DEGs were identified in the corresponding placentas. However, no differences in CpG methylation were observed in fetuses and placentas from the three groups. Imprinting control region methylation and imprinted gene expression were the same between the three fetus and placenta groups. Although 49 repetitive DNA sequences (RS) were abnormally activated in ROSI fetuses, RS DNA methylation did not differ between the three groups. Interestingly, abnormal hypermethylation in promoter regions and low expression of Fggy and Rec8 were correlated with a crown-rump length less than 6 mm in one ROSI fetus. Our study demonstrates that the transcriptome and DNA methylation in ROSI-derived E11.5 mouse fetuses and placentas were comparable with those in the other two groups. However, some abnormally expressed genes in the ROSI fetus and placenta warrant further investigation to elucidate their effect on the development of ROSI-derived embryos.

Spermatogonium-Derived Complete Hydatidiform Mole

A complete hydatidiform mole (CHM) is a conceptus with only sperm-derived chromosomes. Here, we report on a CHM with genomic DNA identical to that of the paternal somatic cells. The CHM developed in a woman who had undergone intrauterine implantation of a blastocyst obtained through in vitro injection of a presumed round spermatid into one of her oocytes. The CHM was genetically identical to peripheral white cells of her husband and contained no maternally derived nuclear DNA. We hypothesize that a spermatogonium, rather than a round spermatid, was inadvertently selected for the procedure. The CHM developed into a gestational trophoblastic neoplasia, which resolved after chemotherapy. (Funded by the Japan Society for the Promotion of Science.).

Effects of SPATA6 on proliferation, apoptosis and steroidogenesis of Hu sheep Leydig cells in vitro

This study aimed to investigate the expression pattern of spermatogenesis associated protein 6 (SPATA6) in Hu sheep testis and to ascertain the effects of SPATA6 on sheep Leydig cells (LCs) function linked to spermatogenesis. In the present study, we detected a 1970 bp cDNA fragment of SPATA6 included a 1467 bp coding sequence which encoded 487 amino acids. Meanwhile, sheep SPATA6 shared 51.70%-97.41% amino acid sequences with its orthologs compared with other species. In addition, SPATA6 was highly expressed in testis and localized in cytoplasm and nucleus of LCs as well as spermatogenic cells at different stages. Compared to the negative control (NC), SPATA6 interference promoted apoptosis of LCs with the increase of BAX/BCL-2 mRNA and protein levels, while the results of SPATA6 overexpression were on the contrary. Meanwhile, cell cycle was blocked at G2/M phase and CDK1 and CCNB1 were down-regulated after SPATA6 interference. SPATA6 overexpression induced cell cycle transfer G0/G1 into S and G2/M phase with upregulation of CDK1, CDK4, CCND1 and CCND2. Moreover, the secretion of testosterone hormone and the expression of StAR in LCs with SPATA6 overexpression were significantly promoted. Overall, our data suggest that SPATA6 is an important functional molecule of spermatogenesis, via regulating the proliferation, apoptosis and testosterone biosynthesis of Hu sheep LCs. These findings will enhance the understanding of the roles of SPATA6 in sheep spermatogenesis.

Round spermatid injection into human oocytes: a systematic review and meta-analysis

Many azoospermic men do not possess mature spermatozoa at the time of surgical sperm extraction. This study is a systematic review and meta-analysis evaluating outcomes following round spermatid injection (ROSI), a technique which utilizes immature precursors of spermatozoa for fertilization. An electronic search was performed to identify relevant articles published through October 2018. Human cohort studies in English involving male patients who had round spermatids identified and used for fertilization with human oocytes were included. Fertilization rate, pregnancy rate, and resultant delivery rate were assessed following ROSI. Meta-analysis outcomes were analyzed using a random-effects model. Data were extracted from 22 studies involving 1099 couples and 4218 embryo transfers. The fertilization rate after ROSI was 38.7% (95% confidence interval [CI]: 31.5%-46.3%), while the pregnancy rate was 3.7% (95% CI: 3.2%-4.4%). The resultant delivery rate was low, with 4.3% of embryo transfers resulting in a delivery (95% CI: 2.3%-7.7%). The pregnancy rate per couple was 13.4% (95% CI: 6.8%-19.1%) and the resultant delivery rate per couple was 8.1% (95% CI: 6.1%-14.4%). ROSI has resulted in clinical pregnancies and live births, but success rates are considerably lower than those achieved with mature spermatozoa. While this technique may be a feasible alternative for men with azoospermia who decline other options, couples should be aware that the odds of a successful delivery are greatly diminished and the prognosis is relatively poor.

Paternal epigenetics: Mammalian sperm provide much more than DNA at fertilization

The spermatozoon is a highly differentiated cell with unique characteristics: it is mobile, thanks to its flagellum, and is very compact. The sperm cytoplasm is extremely reduced, containing no ribosomes, and therefore does not allow translation, and its nucleus contains very closed chromatin, preventing transcription. This DNA compaction is linked to the loss of nucleosomes and the replacement of histones by protamines. Based on these characteristics, sperm was considered to simply deliver paternal DNA to the oocyte. However, some parts of the sperm DNA remain organized in a nucleosomal format, and bear epigenetic information. In addition, the nucleus and the cytoplasm contain a multitude of RNAs of different types, including non-coding RNAs (ncRNAs) which also carry epigenetic information. For a long time, these RNAs were considered residues of spermatogenesis. After briefly describing the mechanisms of compaction of sperm DNA, we focus this review on the origin and function of the different ncRNAs. We present studies demonstrating the importance of these RNAs in embryonic development and transgenerational adaptation to stress. We also look at other epigenetic marks, such as DNA methylation or post-translational modifications of histones, and show that they are sensitive to environmental stress and transmissible to offspring. The post-fertilization role of certain sperm-borne proteins is also discussed.

Infertility considerations in klinefelter syndrome: From origin to management

Klinefelter syndrome (KS) is defined as the presence of one or more extra "X" chromosome in a male patient. It affects approximately 1 in 600 newborn males and the most common chromosomal abnormality, leading to male hypogonadism and infertility. There is a lack of data supporting best practices for KS patients' care. In this paper we review controversial issues in KS research ranging from mechanisms of variation in KS phenotype to abnormalities resulting in reduced sperm production to successful sperm retrieval disparities after testicular sperm extraction (TESE). Translation to live birth and offspring health is also examined. Finally, medical therapies used to optimize the hormonal status and chances of fertility in KS patients are reviewed. We will also discuss the experimental spermatogonial stem cell (SSC) treatments, which are considered the future for TESE negative patients.

Assisted reproductive treatments with hyperbaric oxygen therapy in male infertility

OBJECTIVE

This study aimed to analyze the results of hyperbaric oxygen therapy (HBOT) in addition to assisted reproductive technologies in male infertility cases.

MATERIAL AND METHODS

Medical records of male infertility patients who had HBOT sessions for any reason between January 1, 2015-December 31, 2019, were analyzed retrospectively.

RESULTS

A total of 15 male patients were included. Patients were classified as group 1 [DNA fragmentation (n=5)], group 2 [globozoospermia (n=5)], and group 3 [azoospermia (n=5)]. Round spermatid injection (ROSI), intrauterine insemination (IUI), or intracytoplasmic sperm injection (ICSI) procedures were performed in 10 of the 15 patients. A total of 31 embryos were obtained out of which 19 (61%) were transferred. While a total of 15 embryos were obtained in the globozoospermic group, which was the highest number, 10 were obtained from the azoospermic patients, and 6 from the DNA fragmentation patients (p=0.515). A total of 3 (30%) healthy pregnancies were obtained, overall. The mean sperm count of the patients (n=9) before HBOT was 8.4±11.1 mil/mL, while it was found to be 15.7±15.0 mil/mL after HBOT (azoospermic patients were not included). The TESE results were analyzed for azoospermic patients; positive changes were observed in 4 patients (80%). On the other hand, there was an improvement in 50% of group 1 according to sperm DNA fragmentation after HBOT (p=0.500).

CONCLUSION

While a total of 15 embryos were obtained in the globozoospermic group, which was the highest number, 10 were obtained from the azoospermic patients.. Further studies should be conducted on HBOT and male infertility.

Male reproductive health and intergenerational metabolic responses from a small RNA perspective

The world has recently experienced a decline in male reproductive (e.g. sperm counts and motility) and metabolic (e.g. obesity and diabetes) health. Accumulated evidence from animal models also shows that the metabolic health of the father may influence the metabolic health in his offspring. Vectors for such paternal intergenerational metabolic responses (IGMRs) involve small noncoding RNAs (sncRNAs) that often increase in spermatozoa during the last days of maturation in the epididymis. We and others have shown that the metabolic state - depending on factors such as diet, obesity and physical exercise - may affect sperm quality and sperm sncRNA. Together, this suggests that there are overlapping aetiologies between the male metabolic syndrome, male factor infertility and intergenerational responses. In this review, we present a theoretical framework for an overlap of these aetiologies by exploring the advances in our understanding of the roles of sncRNA in spermatogenesis and offspring development. A special focus will lie on novel findings about tRNA-derived small RNA (tsRNA), rRNA-derived small RNA (rsRNA) and small mitochondrial RNA (mitoRNA), and their emerging roles in intergenerational metabolic and reproductive health.

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.

Germ cell depletion in recipient testis has adverse effects on spermatogenesis in orthotopically transplanted testis pieces via retinoic acid insufficiency

Germ cell depletion in recipient testes is indispensable for successful transplantation of spermatogonial stem cells. However, we found that such treatment had an adverse effect on spermatogenesis of orthotopically transplanted donor testis tissues. In the donor tissue, the frequency of stimulated by retinoic acid (RA) 8 (STRA8) expression was reduced in germ cells, suggesting that RA signalling indispensable for spermatogenesis was attenuated in germ cell-depleted recipient testes. In this context, germ cell depletion diminished expression of testicular Aldh1a2, which is responsible for testicular RA synthesis, while Cyp26b1, which is responsible for testicular RA metabolism, was still expressed even after germ cell depletion, suggesting an alteration of the RA synthesis/metabolism ratio. These observations suggested that RA insufficiency was one of the causes of the defective donor spermatogenesis. Indeed, repetitive RA administrations significantly improved donor spermatogenesis to produce fertile offspring without any side effects. These findings may contribute to improving fertility preservation techniques for males, especially to prevent iatrogenic infertility induced by chemotherapy in prepubertal cancer patients.

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.

Round Spermatid Injection

From a fertility perspective, men with azoospermia represent a challenging patient population. When no mature spermatozoa are obtained during a testicular sperm extraction, patients are often left with limited options, such as adoption or the use of donor sperm. However, it has been reported that round spermatids can be successfully injected into human oocytes and used as an alternative to mature spermatozoa. This technique is known as round spermatid injection (ROSI). Despite the limitations of ROSI and diminished clinical success rates, the use of round spermatids for fertilization may have potential as a treatment modality for men with azoospermia.

Increasing associations between defects in phospholipase C zeta and conditions of male infertility: not just ICSI failure?

PURPOSE

Oocyte activation is a fundamental event at mammalian fertilization. In mammals, this process is initiated by a series of characteristic calcium (Ca²⁺) oscillations, induced by a sperm-specific phospholipase C (PLC) termed PLCzeta (PLCζ). Dysfunction/reduction/deletion of PLCζ is associated with forms of male infertility where the sperm is unable to initiate Ca²⁺ oscillations and oocyte activation, specifically in cases of fertilization failure. This review article aims to systematically summarize recent advancements and controversies in the field to update expanding clinical associations between PLCζ and various male factor conditions. This article also discusses how such associations may potentially underlie defective embryogenesis and recurrent implantation failure following fertility treatments, alongside potential diagnostic and therapeutic PLCζ approaches, aiming to direct future research efforts to utilize such knowledge clinically.

METHODS

An extensive literature search was performed using literature databases (PubMed/MEDLINE/Web of Knowledge) focusing on phospholipase C zeta (PLCzeta; PLCζ), oocyte activation, and calcium oscillations, as well as specific male factor conditions.

RESULTS AND DISCUSSION

Defective PLCζ or PLCζ-induced Ca²⁺ release can be linked to multiple forms of male infertility including abnormal sperm parameters and morphology, sperm DNA fragmentation and oxidation, and abnormal embryogenesis/pregnancies. Such sperm exhibit absent/reduced levels, and abnormal localization patterns of PLCζ within the sperm head.

CONCLUSIONS

Defective PLCζ and abnormal patterns of Ca²⁺ release are increasingly suspected a significant causative factor underlying abnormalities or insufficiencies in Ca²⁺ oscillation-driven early embryogenic events. Such cases could potentially strongly benefit from relevant therapeutic and diagnostic applications of PLCζ, or even alternative mechanisms, following further focused research efforts.

Cell survival after cryopreservation of dissociated testicular cells from feline species

Testicular cell suspension (TCS) can be cryopreserved for male germ-line preservation and fertility restoration. We aimed to validate a cryopreservation protocol for TCS of domestic cat to be applied in endangered felids species. Testis tissue from adult domestic cats was enzymatically dissociated and spermatogenic cells were enriched. The resulting TCS was diluted in 7.5% or 15% Me2SO based medium. Slow and fast freezing methods were tested. We examined the effects of freezing approaches using two combinations of fluorescent dyes: Calcein-AM with Propidium iodide (C/PI) and SYBR14 with Propidium iodide (S/PI). Ploidy analysis of domestic cat fresh TCS revealed that the majority of testicular cells were haploid cells. Based on microscopic observation, two size populations (12.3 ± 2.3 μm and 20.5 ± 4 μm in diameter) were identified and presumed to be mainly spermatids and spermatocytes, respectively. Both evaluation methods proved higher viability of aggregated cells before and after cryopreservation compared with single cells, and superiority of low concentration of Me2SO (7.5%) in association with slow freezing to preserve viability of testicular cells. However, S/PI resulted in a more precise evaluation compared with the C/PI method. The combination of 7.5% Me2SO-based medium with slow freezing yielded post thaw viability of S/PI labeled aggregated (49.8 ± 20%) and single cells (31.5 ± 8.1%). Comparable results were achieved using testes of a Cheetah and an Asiatic golden cat. In conclusion, TCS from domestic cat can be successfully cryopreserved and has the potential to support fertility restoration of endangered felids species.

Oocyte activation, oolemma piercing, and real-time viability confirmation in human oocytes using electrophysiological techniques

PURPOSE OF REVIEW

To discuss the recent applications of electrophysiological principles to the optimization and automation of the IVF laboratory.

RECENT FINDINGS

There is growing evidence showing improvement of live birth rates following oocyte electro-activation. Novel applications using electrophysiological techniques are now employed to determine oocyte penetration and viability in real-time.

SUMMARY

In this short review, we summarize the recent advances in the integration of electrophysiological techniques into the assisted reproductive technology laboratories. We describe the potential clinical applications and their advantages such as creation of reliable automated cell injection systems and novel manual intracytoplasmic sperm injection (ICSI) training platforms. We also discuss theoretical adverse effects and ways to mitigate them.

Progress in translational reproductive science: testicular tissue transplantation and in vitro spermatogenesis

Since the birth of the first child conceived via in vitro fertilization 40 years ago, fertility treatments and assisted reproductive technology have allowed many couples to reach their reproductive goals. As of yet, no fertility options are available for men who cannot produce functional sperm, but many experimental therapies have demonstrated promising results in animal models. Both autologous (stem cell transplantation, de novo morphogenesis, and testicular tissue grafting) and outside-the-body (xenografting and in vitro spermatogenesis) approaches exist for restoring sperm production in infertile animals with varying degrees of success. Once safety profiles are established and an ideal patient population is chosen, some of these techniques may be ready for human experimentation in the near future, with likely clinical implementation within the next decade.

Increased DNA methylation in the spermatogenesis-associated (SPATA) genes correlates with infertility

BACKGROUND

Spermatogenesis-associated (SPATA) family of genes plays important roles in spermatogenesis, sperm maturation or fertilization. The knockout studies in mice have demonstrated that SPATA genes are crucial for fertility. Gene expression and genetic polymorphism studies have further suggested their correlation with infertility; however, methylation analysis of SPATA genes in human male infertility has not yet been undertaken.

OBJECTIVES

To analyze the methylation status of SPATA4, SPATA5 and SPATA6 genes in oligozoospermic male infertility.

MATERIALS AND METHODS

In the present study, we have analyzed DNA methylation pattern in the promoter regions of SPATA4, SPATA5 and SPATA6 genes in oligozoospermic patients and compared it with normozoospermic fertile controls. Semen samples were obtained from 30 oligozoospermic infertile and 19 normozoospermic fertile controls, and DNA methylation levels of the target gene promoters were analyzed by amplicon based deep sequencing methylation analysis using MiSeq.

RESULTS

SPATA4 (P < 0.0008), SPATA5 (P = 0.009) and SPATA6 (Promoter, P < 0.0005; Exon 1, P = 0.0128) genes were significantly hypermethylated in oligozoospermic patients in comparison to controls. This is the first study reporting a higher methylation in the promoters of SPATA4, SPATA5 and SPATA6 in oligozoospermic infertile individuals in comparison to the normozoospermic fertile controls.

DISCUSSION

Altered methylation of SPATA genes would affect pathways involved in sperm production or affect various processes linked to sperm fertility.

CONCLUSION

In conclusion, hypermethylation in the SPATA4, SPATA5 and SPATA6 genes correlates with oligozoospermic infertility.

Urine-Derived Stem Cells Facilitate Endogenous Spermatogenesis Restoration of Busulfan-Induced Nonobstructive Azoospermic Mice by Paracrine Exosomes

Nonobstructive azoospermia (NOA) is a severe form of male infertility, with limited effective treatments. Urine-derived stem cells (USCs) possess multipotent differentiation capacity and paracrine effects, and participate in tissue repair and regeneration. The aim of this study is to investigate whether the transplantation of USCs or USC exosomes (USC-exos) could promote endogenous spermatogenesis restoration in a busulfan-induced NOA mice model. USCs were cultured and characterized by flow cytometry. High-density USCs were cultured in a hollow fiber bioreactor for exosomes collection. USC-exos were isolated from USCs conditional media and identified by transmission electron microscopy, western blotting, and Flow NanoAnalyzer analysis. USC-exos exhibited sphere- or cup-shaped morphology with a mean diameter of 66.5 ± 16.0 nm, and expressed CD63 and CD9. USCs and USC-exos were transplanted into the interstitial space in the testes of NOA mice per the following groups: normal group; groups treated with no injection, phosphate-buffered saline (PBS), USCs or USC-exos on days 3 and 36 after busulfan administration, respectively. Thirty days after USCs and USC-exos transplantation, spermatogenesis was restored by both USCs and USC-exos in NOA mice 36 days after busulfan treatment as confirmed by immunofluorescence staining and hematoxylin and eosin staining. Moreover, spermatogenic genes (Pou5f1, Prm1, SYCP3, and DAZL) and the spermatogenic protein UCHL1 were significantly increased in both the USCs 36 and USC-exos36 groups compared with the PBS group, as demonstrated using quantitative real-time polymerase chain reaction and western blot analysis. However, the transplantation of USCs or USC-exos at day 3 after busulfan treatment did not improve spermatogenesis in NOA mice. Our study demonstrated that USCs could facilitate endogenous spermatogenesis restoration of busulfan-induced NOA mice through paracrine exosomes but could not protect the mouse testicles at the early stage of destruction caused by busulfan. This study provides a novel insight into the treatment of NOA.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.