Circulatory exosomal tRF-Glu-CTC-005 and tRF-Gly-GCC-002 serve as predictive factors of successful microdissection testicular sperm extraction in patients with nonobstructive azoospermia

Human sperm RNA in male infertility

The function and value of specific sperm RNAs in apparently idiopathic male infertility are currently poorly understood. Whether differences exist in the sperm RNA profile between patients with infertility and fertile men needs clarification. Similarly, the utility of sperm RNAs in predicting successful sperm retrieval and assisted reproductive technique (ART) outcome is unknown. Patients with infertility and fertile individuals seem to have differences in the expression of non-coding RNAs that regulate genes controlling spermatogenesis. Several RNAs seem to influence embryo quality and development. Also, RNA types seem to predict successful sperm retrieval in patients with azoospermia. These findings suggest that sperm RNAs could influence decision-making during the management of patients with infertility. This evidence might help to identify possible therapeutic approaches aimed at modulating the expression of dysregulated genes in patients with infertility. Performing prospective studies with large sample sizes is necessary to investigate cost-effective panels consisting of proven molecular targets to ensure that this evidence can be translated to clinical practice.

Epigenetics of nonobstructive azoospermia

Nonobstructive azoospermia (NOA) is a severe and heterogeneous form of male factor infertility caused by dysfunction of spermatogenesis. Although various factors are well defined in the disruption of spermatogenesis, not all aspects due to the heterogeneity of the disorder have been determined yet. In this review, we focus on the recent findings and summarize the current data on epigenetic mechanisms such as DNA methylation and different metabolites produced during methylation and demethylation and various types of small noncoding RNAs involved in the pathogenesis of different groups of NOA.

Circulating serum exosomes i-tRF-AspGTC and tRF-1-SerCGA as diagnostic indicators for non-small cell lung cancer

BACKGROUND

tRF-RNA-a representative of non-coding RNA (ncRNA)-is a precursor or fragment of mature tRNA and plays a crucial regulatory role in the occurrence and development of cancer. There is currently little research on tRF-RNA as a diagnostic marker in cancer, especially for NSCLC from serum exosomes.

METHOD

Serum exosomes were successfully extracted from serum; their physical morphology was captured by transmission electron microscopy (TEM); appropriate particle size detection was performed using qNano; surface labeling was verified through western blotting. Serum exosomes i-tRF-AspGTC and tRF-1-SerCGA were selected through gene microarray, and qPCR was used to validate their significance in 242 patients and 201 healthy individuals. The area under the curve (AUC) was used to evaluate the diagnostic indicators of non-small cell lung cancer (NSCLC).

RESULT

Compared with 201 healthy individuals, i-tRF-AspGTC and tRF-1-SerCGA were significantly downregulated in 242 NSCLC patients and 95 early-stage patients. For tRF-AspGTC and tRF-1-SerCGA, the predictive diagnostic efficiency rates of AUC were 0.690 and 0.680, respectively, whereas the early diagnostic efficiency rates were 0.656 and 0.688, respectively. The result of combined diagnosis with CEA and CYFRA21-1 was 0.928, and the early diagnostic efficiency was 0.843, which is a very high biological predictive factor for NSCLC.

CONCLUSION

The expression of serum exosomes i-tRF-AspGTC and tRF-1-SerCGA was significantly downregulated in NSCLC patients. These exosomes could be used as predictive indicators for diagnosis or early diagnosis of NSCLC.

Clinical predictors of successful outcomes for couples with nonobstructive azoospermic male partners undergoing micro-TESE

ABSTRACT

Nonobstructive azoospermia (NOA) is the most challenging and complex clinical scenario for infertile men. Besides circumstances such as hypogonadotropic hypogonadism, surgical sperm retrieval is typically necessary, and microdissection testicular sperm extraction (micro-TESE) is the procedure of choice for men with NOA desiring to father children with their own gametes. Micro-TESE results in the highest numbers of sperm cells retrieved for use with in vitro fertilization/intracytoplasmic sperm injection (ICSI) in comparison to all other techniques for surgical sperm retrieval in men with NOA. Several factors may affect sperm retrieval rate and ICSI outcomes, including the patient's age, testicular volume, histopathological and genetic profile, and serum hormone levels. This article aims to review the medical literature describing predictors of successful micro-TESE and the outcomes of ICSI in men with NOA.

Clinical management of nonobstructive azoospermia: An update

Approximately 1% of the general male population has azoospermia, and nonobstructive azoospermia accounts for the majority of cases. The causes vary widely, including chromosomal and genetic abnormalities, varicocele, drug-induced causes, and gonadotropin deficiency; however, the cause is often unknown. In azoospermia caused by hypogonadotropic hypogonadism, gonadotropin replacement therapy can be expected to produce sperm in the ejaculate. In some cases, upfront varicocelectomy for nonobstructive azoospermia with varicocele may result in the appearance of ejaculated spermatozoa; however, the appropriate indication should be selected. Each guideline recommends microdissection testicular sperm extraction for nonobstructive azoospermia in terms of successful sperm retrieval and avoidance of complications. Sperm retrieval rates generally ranged from 20% to 70% but vary depending on the causative disease. Various attempts have been made to predict sperm retrieval and improve sperm retrieval rates; however, the evidence is insufficient. Further evidence accumulation is needed for salvage treatment in cases of failed sperm retrieval. In Japan, there is inadequate provision on the right to know the origin of children born from artificial insemination of donated sperm and the rights of sperm donors, as well as information on unrelated family members, and the development of these systems is challenging. In the future, it is hoped that the pathogenesis of nonobstructive azoospermia with an unknown cause will be elucidated and that technology for omics technologies, human spermatogenesis using pluripotent cells, and organ culture methods will be developed.

The emerging role of extracellular vesicles in the testis

Extracellular vesicles (EVs) are nano-sized membrane-bounded particles, released by all cells and capable of transporting bioactive cargoes, proteins, lipids, and nucleic acids, to regulate a variety of biological functions. Seminal plasma is enriched in EVs, and extensive evidence has revealed the role of EVs (e.g. prostasomes and epididymosomes) in the male genital tract. Recently, EVs released from testicular cells have been isolated and identified, and some new insights have been generated on their role in maintaining normal spermatogenesis and steroidogenesis in the testis. In the seminiferous tubules, Sertoli cell-derived EVs can promote the differentiation of spermatogonial stem cells (SSCs), and EVs secreted from undifferentiated A spermatogonia can inhibit the proliferation of SSCs. In the testicular interstitium, EVs have been identified in endothelial cells, macrophages, telocytes, and Leydig cells, although their roles are still elusive. Testicular EVs can also pass through the blood-testis barrier and mediate inter-compartment communication between the seminiferous tubules and the interstitium. Immature Sertoli cell-derived EVs can promote survival and suppress the steroidogenesis of Leydig cells. Exosomes isolated from macrophages can protect spermatogonia from radiation-induced injury. In addition to their role in intercellular communication, testicular EVs may also participate in the removal of aberrant proteins and the delivery of antigens for immune tolerance. EVs released from testicular cells can be detected in seminal plasma, which makes them potential biomarkers reflecting testicular function and disease status. The testicular EVs in seminal plasma may also affect the female reproductive tract to facilitate conception and may even affect early embryogenesis through modulating sperm RNA. EVs represent a new type of intercellular messenger in the testis. A detailed understanding of the role of testicular EV may contribute to the discovery of new mechanisms causing male infertility and enable the development of new diagnostic and therapeutic strategies for the treatment of infertile men.

Modern surgical treatment of azoospermia

PURPOSE OF REVIEW

To review noteworthy research from the last 2 years on surgical management of azoospermia.

RECENT FINDINGS

The recommended treatments for nonobstructive and obstructive azoospermia have not appreciably changed. However, recent level-1 evidence has reinforced superiority of micro-dissection testicular sperm extraction over sperm aspiration in men with nonobstructive azoospermia, and several studies have identified genetic and other clinical factors that may aid in selecting candidates for testicular sperm extraction. Machine learning technology has shown promise as a decision support system for patient selection prior to sperm retrieval as well a tool to aid in sperm identification from testis tissue.

SUMMARY

Most men with obstructive azoospermia who desire fertility can be offered either surgical reconstruction or sperm retrieval. For men with nonobstructive azoospermia, sperm retrieval with microdissection testicular sperm extraction remains the gold standard treatment. Uncovering more genetic causes of nonobstructive azoospermia may aid in properly counseling and selecting patients for microdissection testicular sperm extraction. Neural networks and deep learning may have a future role in patient selection for surgical sperm retrieval and postprocedural sperm identification.

The Clinical Significance of Transfer RNAs Present in Extracellular Vesicles

Extracellular vesicles (EVs) are important for intercellular signalling in multi-cellular organisms. However, the role of mature transfer RNAs (tRNAs) and tRNA fragments in EVs has yet to be characterised. This systematic review aimed to identify up-to-date literature on tRNAs present within human EVs and explores their potential clinical significance in health and disease. A comprehensive and systematic literature search was performed, and the study was conducted in accordance with PRISMA guidelines. Electronic databases MEDLINE and EMBASE were searched up until 1 January 2022. From 685 papers, 60 studies were identified for analysis. The majority of papers reviewed focussed on the role of EV tRNAs in cancers (31.7%), with numerous other conditions represented. Blood and cell lines were the most common EV sources, representing 85.9% of protocols used. EV isolation methods included most known methods, precipitation being the most common (49.3%). The proportion of EV tRNAs was highly variable, ranging between 0.04% to >95% depending on tissue source. EV tRNAs are present in a multitude of sources and show promise as disease markers in breast cancer, gastrointestinal cancers, and other diseases. EV tRNA research is an emerging field, with increasing numbers of papers highlighting novel methodologies for tRNA and tRNA fragment discovery.